Remove start index 0 in range()

Remove the useless arg ("start index" = 0) in files, since its default
value is 0, to make code cleaner.

Change-Id: I9d91ab8a8033b9a6c9b77608dea92c91a994c7fc
Glance GET /v2/images fails with 500 due to erroneous policy check

This patch will fix below two issues of V2 ResponseSerializer for
images-list, image-show, image-update and image-download.

1. A user should be able to list/show/update/download image without
needing permission on get_image_location.
2. A policy failure should result in a 403 return code. We're
getting a 500.

Fixes bug 1231255

Change-Id: Ie0ec2d574eea4433c4f610ec66a22cb16cae6dc6
Update functional tests for swift changes

It seems that a couple of changes to the store calls have slipped
through unnoticed:

* store.add() now returns a 4-tuple
* x-container-read and x-container-write headers use tenant:user rather
  than just tenant.

fixes bug 1236339

Change-Id: Ic5c311bcc2999e13203e0d3ad37bce5ac5f27e2d
Fixes rbd _delete_image snapshot with missing image

Also ignore if _delete_image returns NotFound when cleaning up
following failed attempt to create a new image with add().

Also added unit tests.

Change-Id: Id66866b4260385a6324cc277c5ac665f81493c89
Fixes: bug 1233097
Merge "Remove start index 0 in range()"
Merge "Glance GET /v2/images fails with 500 due to erroneous policy check"
Merge "Fixes rbd _delete_image snapshot with missing image"
Merge "Update functional tests for swift changes"