005_encoding.pl neglected to wait for the subscriber's initial
synchronization to happen.  While we have not seen this fail in
the buildfarm, it's pretty easy to demonstrate there's an issue
by hacking logicalrep_worker_launch() to fail most of the time.

Michael Paquier

Discussion: https://postgr.es/m/27032.1505749806@sss.pgh.pa.us