webadmin : mouse hover in volumes Activities column shows a box

Drop down menu in Activities column for volumes should have a box on mouse hover

Change-Id: I807ac3fd92ef91f5524148f768cf176f3e811614
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1019559
Signed-off-by: Anmol Babu <anbabu@redhat.com>