(MODULES-630) Deprecate postgresql::server::version

Adjusting the version is explicitly done though the postgresql::globals
class, as this affects many parts of the module. This parameter did not
function correctly on systems that did not have a default, as described
in the ticket.
Merge pull request #407 from hunner/deprecate_version

(MODULES-630) Deprecate postgresql::server::version
Attempt at fixing master branch tests.
Mark postgis as unavailable on RHEL7.
Add RHEL7 support and disable external repos for now.
The /etc/sysconfig/pgsql doesn't exist on RHEL7.
Ensure the service has started at least once before reloading.
Add `service_ensure` so we can control services, then use it during
the validate_db_connection_spec tests.
fix.
Try.
More.
Fix.
Fix.
e
In RHEL7 we have to handle the port via Systemd.
Merge branch 'rhel7' of https://github.com/apenney/puppetlabs-postgresql into rhel7