BUG #6405: postgres account not created during unattended install

The following bug has been logged on the website:

Bug reference: 6405
Logged by: Mark Phillips
Email address: mark.phillips@mophilly.com
PostgreSQL version: 9.1.2
Operating system: Mac OS X 10.7
Description:

for a stand alone app that uses postgres, the app installer invokes the
shell script installbuilder.sh for the "unattended" install of postgres.

The pg installer creates a user "PostgreSQL" that is not hidden, but does
not create a hidden account "postgres". As a result, the invocation of
pg_ctl fails. Error is "unknown login: postgres".