BUG #14961: 9.6.6-4PGDG.rhel6.x86_64 introduces hanging init script

The following bug has been logged on the website:

Bug reference:      14961
Logged by:          Fikkie de Hond
Email address:      171211@vmlinuz.nl
PostgreSQL version: 9.6.6
Operating system:   CentOS6
Description:

The update from 
postgresql96-server-9.6.6-3PGDG.rhel6.x86_64 to 9.6.6-4PGDG.rhel6.x86_64
changed the /etc/init.d/postgresql-9.6 script in such a way that any
start/condrestart hangs the script. The & to fork the starting server is
gone. Even the %post script from the rpm cannot perform its condrestart
without hanging.