This patch adds the supported driver checks to the
Fibre Channel Zone Manager. This is the same mechanism
that is in Cinder volume drivers.
When a zone manager driver is marked as unsupported, the zone manager
won't allow it to work unless the enable_unsupported_driver=True is
added to the fc-zone-manager section in cinder.conf
Change-Id: If707b9005f60dc28eb99f46929fb700a2de0f755
Implements: blueprint zonemanager-supported-driver