BUG #12072: init script creates pid file with wrong owner

The following bug has been logged on the website:

Bug reference:      12072
Logged by:          Henrik Storner
Email address:      henrik-postgres@hswn.dk
PostgreSQL version: 9.3.5
Operating system:   CentOS 6.6
Description:

The /etc/init.d/postgresql-9.3 file created a PID file, but fails to make it
owned by user 'postgres'.

This means that using the "pg_ctl" command to restart Postgres fails,
because user postgres cannot update the pid file (if you set
external_pid_file in postgresql.conf so it can find the pid file).

The init script should do a "chown postgres:postgres $pidfile" so the pid
file is owned by the postgres user. This allows pg_ctl commands to work.