Sometimes we want to hide certain UI elements depending on the
permissions granted to the current user. At the moment this is
possible for Actions and Panels. This commit extends support to
DataTable too.
We also set the permission on the volume snapshots table so that,
like the volumes panel, it is only displayed when the 'volume'
service is active.
Fixes bug #1087128.
Change-Id: Icc12b479c3eb888320af735b8b7810e58517eef0
eab5fc7712