Blueprint manual-slave-to-master: review fixes

Sweep out the first set of coding bugs in the test suite:
- set slab_alloc_arena to 0.05 in all box_replication configurations,
since otherwise this suite tries to allocate too much memory
and hangs under a VM.
- update some texts that make it into the log (spelling)
- add logging to all configurations
- simplify wait_sync and rename it to wait_lsn
- there was a bug in wait_sync that time.sleep() was
not called in the body of the loop due to \t, and
the loop was a busy-wait one.