webadmin: hide PM alert for gluster host

PM not enabled warning('!' mark) will not be shown
for the hosts which belongs to gluster-only cluster.

Change-Id: I4af11175ee27cdbed2e11f242af936945c8e486c
Bug-Url: https://bugzilla.redhat.com/955491
Signed-off-by: Kanagaraj M <kmayilsa@redhat.com>