(pdb-775) Retire old postgres versions

This commit retires support for all postgres versions less than 9.3,
which means we are no longer deprecating any databases. This commit
keeps around the old deprecation logic for future use and updates the
versions we do not support to include all postgres versions <9.3. This
commit also updates our acceptance test helpers to install postgres from
the upstream packages on the postgres site so that our tests always use
9.3.
(PDB-775) Add pgsql binary locations to PATH for read-only db test

This commit addresses an issue where the system pgsql binaries
(specifically older versions) were being used when making a read-only
database for puppetdb which caused puppetdb2 to be empty. This commit
fixes this issue by adding all possible binary locations of pgsql-9.3
binaries to PATH.
(PDB-775) Update operators doc link for psql 9.3

This commit updates the link for regexps in psql by changing the version
to 9.3.
(PDB-775) Remove check for deprecated postgres versions

This commit removes the check for deprecated postgres versions since we
are no longer deprecating any versions of postgres.
Merge pull request #1172 from ajroetker/pdb-775_retire_old_psqls

(pdb-775) Retire old postgres versions