pgsql: fix hostname parsing
pgsql: fix hostname parsing

The current PostgreSQL driver only look for the host option in URL,
whereas it should also look for the hostname in the URL!

This patch makes sure you can override URL values with options, but also
read those URL values.

Change-Id: I70a13c2f61bdd3a04fd2b0ed4cbf8b2ca96cfec6

openstack/tooz,openstack/tooz