(PDB-4579) fix connection tests
(PDB-4579) fix connection tests

PostgreSQL JDBC driver has a bug where the isValid() call on a
connection does not respect timeouts. This causes our connection pool to
not detect a dead connection, which will eventually exhaust our
connection pool entirely. See pgjdbc/pgjdbc#1557

puppetlabs/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb,puppetlabs/puppetdb