gluster: fix for host getting removed when moved to maintenance(#980750)

Now the host will not be eligible for removal when in maintenance state.

Change-Id: Ib4cde89b8eff57be9a6c89735f6269dd57559f50
Bug-Url: https://bugzilla.redhat.com/show_bug.cgi?id=980750
Signed-off-by: ndarshan <dnarayan@redhat.com>