core, webadmin: VDSGroupHostsAndVMs equals

- Fixed VDSGroup equals to return true when two VDSGroups are
  actually the same. Since VDSGroupHostsAndVMs did not have a proper
  equals, the VDSGroup equals failed causing loading indicators to show on
  automatic refreshes in the cluster sub tabs.

Change-Id: Iab51ef7ac2e456988b640378d3ab0ea98039af7f
Signed-off-by: Alexander Wels <awels@redhat.com>