The new command is supposed to supersede IPROTO_REQUEST_VOTE, which is
difficult to extend, because it uses the global iproto key namespace.
The new command returns a map (IPROTO_BALLOT), to which we can add
various information without polluting the global namespace. Currently,
the map contains IPROTO_BALLOT_IS_RO and IPROTO_BALLOT_VCLOCK keys,
but soon it will be added info needed for replica rebootstrap feature.

Needed for #461

_say function was called with invalid arguments.
Thank @sorc1 for patch.

Closes #3433.

Strdup may silently fail without any message from tarantool.
Patch adds this checks.

Strings containing "true" and "false" were converted
to a boolean type when serializing. Fixed.
Example:
type(yaml.decode(yaml.encode('false'))) == string
type(yaml.decode(yaml.encode('true'))) == string

Closes #3476.

Function tonumber64 has worked incorrectly with values less
than INT64_MAX.
Now it works in the interval [INT64_MAX, UINT64_MAX] returning
nil otherwise.

Closes #3466.

Net.box didn't pass options containing iterator to
server side.
There were also invalid results for two :count tests in
net.box.result file.

Thanks @ademenev for contributing problem and help with
problem locating.

Closes #3262.

Currently, this function takes a single boolean argument, but I'm
planning to add another one. Since two bool arguments look rather
confusing, let's turn this arguments into flags.

Needed for #461

A small cleanup to avoid a potentially inefficient use of
gc_consumer_vclock().

Follow up on a patch for gh-461.

In order to check if a replica needs to be rebootstrapped, we need to
know the vclock of the oldest WAL stored on the master, but the garbage
collector works with signatures and hence can't report the vclock it was
last called for. Actually, all gc users have a vclock and can pass it
instead of signature so it's pretty easy to switch garbage collection
infrastructure to vclock.

Needed for #461

We will need it in other places.

 - Remove extra scan of the WAL directory from local_recovery() - we
   scan the directory in recovery_end_vclock() hence we can skip scan in
   recover_remaining_wals() by passing scan_dir = false.

 - Rename recovery_end_vclock() to recovery_scan() to emphasize the fact
   that this function scans the WAL directory. Write a comment to this
   function.

 - Add comments to wal.c explaining why we scan the WAL directory there.

Follow-up 0695fbbb ("box: retrieve end vclock before starting local
recovery").

To bring crash_expected option of "start server" command.

There were no checks for granting and revoking a non-existent
privilege or a privilege to a non-existent entity.
Added the checks, and a test case.

Closes #3417

Net.box didn't pass options containing iterator to
server side.
There were also invalid results for two :count tests in
net.box.result file.

Thanks @ademenev for contributing problem and help with
problem locating.

Closes #3262.

If is_first_insert flag is set and vy_stmt_type(rv->tuple) equals
IPROTO_DELETE, we free rv->tuple, but then we dereference it via
an on-stack variable to check if we need to turn a REPLACE into an
INSERT or vice versa. Fix this.

This is not necessary, as we can use fiber()->gc, as we usually do.

Move key_def creation to compare_write_iterator_results as it is the
same for all test cases. Performance is not an issue here, obviously, so
we can close our eyes to the fact that now we create a new key def for
each test cases.

The new function inserts a new item into the list at the specified
postion.

If a fiber pool reuses already canceled fiber then the fiber reports an
error for any next request. Now canceled fiber returns and fiber pool
creates a new one.

Fixes #3527

New commit in third_party/libyaml downgrades
required cmake version.

Need to update tests as with fixup in upstrem
commit baf636a74b4b6d055d93e2d01366d6097eb82d90
Author: Tina Müller <cpan2@tinita.de>
Date:   Thu Jun 14 19:27:04 2018 +0200

The closing single quote needs to be indented...
if it's on its own line.

Closes #3275.

Closes #3275.

Found by @ImeevMA

 - Factor out local_recovery() from box_cfg_xc(). Make it setup
   replication and handle local recovery and hot standby cases.
 - Move replication setup in case of initial bootstrap from box_cfg_xc()
   to bootstrap() to make bootstrap() consistent with local_recovery().
 - Move initial snapshot creation from bootstrap() to bootsrap_master()
   and bootstrap_from_master().

Needed for #461

box_sync_replication() can now be called before recovery, right after
box_listen(). This is a step toward detecting if the instance fell too
much behind its peers in the cluster and so needs to be rebootstrapped.

Needed for #461

In order to find out if the current instance fell too much behind its
peers in the cluster and so needs to be re-bootstrapped we need to
connect it to remote peers before proceeding to local recovery. The
problem is box.cfg.replication may have an entry corresponding to the
instance itself so before connecting we have to start listening to
incoming connections. So this patch moves the call to box_listen()
before recoery is started unless the instance in hot standby mode.
It also folds box_bind() into box_listen() as it is no longer needed
as a separate function.

Needed for #461

In order to find out if the current instance fell too much behind its
peers in the cluster and so needs to be rebootstrapped, we need to know
its vclock before we start local recovery. To do that, let's scan the
most recent xlog. In future, we can optimize that by either storing end
vclock in xlog eof marker or by making a new xlog on server stop.

Needed for #461

Introduce vclock_is_set() helper and use it on xlog_meta::prev_vclock
instead.

Follow-up ac90b498 ("xlog: store prev vclock in xlog header").

Store replication group id in vylog and ignore spaces whose group_id
equals GROUP_LOCAL when relaying initial join rows.

Folow-up #3443

Follow-up #3443

Replica local spaces can't cause replication conflicts so we don't
really need to respect box.cfg.read_only for them (they are similar
to temporary spaces in this regard).

Follow-up #3443

Next checkpoint time is set by the formula:
 period = self.checkpoint_interval + offset,
where offset is defined as follow:
 offset = random % self.checkpoint_interval

So offset must be calculated again if at least the new
interval is less than the old one.

Closes #3370