Add unit tests for glance.api.cached_images module

Add positive unit tests for methods:
* get_chached_images
* delete_cached_images
* get_queued_images
* queue_image
* delete_queued_image

Fixes: bug #1155188
Change-Id: I3fa6dc28a72e8c6e8402911931fb37e18cba7ea0
Fix the deletion of a pending_delete image.

Return '403 - Forbidden' when trying to delete
a 'pending_delete' image, and does not change
its status.

Change-Id: Id5b8b31c19d0f9da8aba66b06d1b966e9c33a363
Fixes: bug #1163020
Fix Qpid test cases

The Qpid notification test cases do not currently pass.
By default they are skipped because qpid is not part of
test-requires, so it isn't automatically installed.  This fix
updates the test cases to work correctly, but does not add
qpid to test-requires because I'm unsure what impacts that
might have on other platforms.

This is part of the fix for bug 1164681

Change-Id: I40757b5de99559b4ff090e0d249f8624c2e2be10
Merge "Fix the deletion of a pending_delete image."
Merge "Fix Qpid test cases"
Merge "Add unit tests for glance.api.cached_images module"