webadmin: snapshots sub-tab - info on active vm

VMs -> Snapshots sub-tab:
As GetVmConfigurationBySnapshot query already supports retrieving
information for active snapshot, update snapshot info tab when
selecting 'Active VM' snapshot.

Change-Id: I1327b8787cc1f07227247ded8b6d3a32baf8ef7a
Signed-off-by: Daniel Erez <derez@redhat.com>