Move commit payload propagation

Move commit payload propagation

Since Shard.persistPayload() will shortcut when we do not have
a followers or persistence, we must update metadata before we
notify the cohort of the success, as for commit-immediate
transactions that will result in a purge payload being persisted.
That payload will shortcut, too, and execute on stack, hence
metadata will see purge before commit -- leaving it in inconsistent
leaky state.

Move allMetadataCommittedTransaction() calls from
applyReplicatedPayload() down to just after we modify the data
tree and before we invoke listeners.

Change-Id: I1ed2f62756367982cfff08302c79f1c63a871df2
JIRA: CONTROLLER-1746
Signed-off-by: Robert Varga <robert.varga@pantheon.tech>