webadmin: snapshot preview - display entities in description

VMs -> Snapshots:
when previewing a snapshot, display previewed entities under
description column (see screenshot).

Screenshot: http://i.imgur.com/JlWWZkZ.png

Change-Id: I2345339fd61cf273224b565c60745fddb64c6ab3
Bug-Url: https://bugzilla.redhat.com/1126211
Signed-off-by: Daniel Erez <derez@redhat.com>