Change 'multiattach' property support status to HIDDEN
From queens release this is an extra-spec capability of volume type and
the ability to attach a volume to multiple hosts/servers requires that
the volume is of a special type that includes an extra-spec capability
setting of multiattach=<is> True.
Address v1 designate client removal from python-designateclient
designateclient v1 has been removed and we need to stop testing
it with client plugin.
Change-Id: I6fd022ea6cabfb7fadf49152babd215e07f8bec1