(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.
Ensure ruby 2.1.8 is not matched as ruby 1.8 

Just in case
(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.
Merge pull request #1180 from sathieu/patch-2

Ensure ruby 2.1.8 is not matched as ruby 1.8
(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.
(PDB-644) Retire node-ttl-days

Completely remove support and tests for [database] node-ttl-days.
Specifying it in the config file will now cause a validation error.
Merge pull request #1173 from rbrw/ticket/master/pdb-644-retire-node-ttl-days

(PDB-644) Retire node-ttl-days
Merge pull request #1172 from ajroetker/pdb-775_retire_old_psqls

(pdb-775) Retire old postgres versions
(PDB-775) Tidy up acceptance helper for package based installs

This commit fixes an issue with package based acceptance tests
whereby we weren't applying the correct manifest for managing puppetdb
on either embedded or postgres puppetdb installs. The hsql issue was due
to the fact we weren't passing in `:embedded` to the module causing the
module to try and validate a postgres database, the postgres issue was
due to the fact that the db param to install_puppetdb is a keyword and
not a string so we were always applying the incorrect hsqldb manifest.