Fix images/snapshots table pagination

For project images, disable pagination entirely as it's not compatible
with client-side filtering (at least without moving to asynch table
loading). This can be revisited when we move to glance v2, which
apparently supports filtering by owner.

For snapshots and admin images, fix pagination by making sure the
iterator returned by glanceclient isn't exhausted completely when
returning a page of images. Do this by slicing just the number of
images we require (+ 1 to check if there will be another page after
this one).

Fixes bug #1083034.

Change-Id: I692f57dec6dca16cf8909f5b234aadb002702fc8
Merge "Fix images/snapshots table pagination"