replication: check rs uuid on subscribe process

Remote node doing the subscribe might be from a different
replicaset.

Before this patch the subscribe would be retried infinitely
because the node couldn't be found in _cluster, and the master
assumed it must have joined to another node, and its ID should
arrive shortly (ER_TOO_EARLY_SUBSCRIBE).

The ID would never arrive, because the node belongs to another
replicaset.

The patch makes so the master checks if the peer lives in the same
replicaset. Since it is doing a subscribe, it must have joined
already and should have a valid replicaset UUID, regardless of
whether it is anonymous or not.

Correct behaviour is to hard cut this peer off immediately,
without retries.

Closes #6094
Part of #5613