webadmin : The menu option "Rebalance" made to appear after "Stop" in Volume tab

The menu option "Rebalance" made to appear after "Stop" in Volume tab

Change-Id: I048a7183311f98760aee53628bb3974416a17344
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=1019557
Signed-off-by: Anmol Babu <anbabu@redhat.com>