Fixes to "could not find user postgres" errors and DS-1889 changes

This PR fixes two issues:

1. Upgrade 'puppetlabs/postgresql' module to version 3.3.0.  The version "3.1.0" of this module doesn't seem to work properly with the latest version of Puppet.  Using it causes an error like: 
"Error: Could not set 'directory' on ensure: Could not find user postgres
at 49:/etc/puppet/modules/concat/manifests/setup.pp"

2. The fix to DS-1889 renames the default ant installer directory on DSpace/DSpace 'master' branch. So, we need to change our default settings for "ant_installer_dir" accordingly. See also: https://jira.duraspace.org/browse/DS-1889

Both of these bug fixes have been verified by Hardy & I.  I'll merge them shortly.