Setting up binary replication between two PostgreSQL instances
Your last two steps are in the wrong order. 

The appropriate steps says


  
  _ 5. Start the standby first, so that they can't get out of sync. (Messages will be logged about not being able to connect to the
  primary server, that's OK.)
  _6. Start the master.
  


You are supposed to start the master after the standby.

Try reversing everything as follows:


[root@dbrepa]# service postgresql-9.2 stop
[root@dbrepb]# service postgresql-9.2 stop
rsync everything from Master (except the pg_xlog and config files (Your Step 4)) to Standby
[root@dbrepb]# service postgresql-9.2 start
[root@dbrepa]# service postgresql-9.2 start


Give it a Try !!!