Disallow access/modify members of deleted image

It should not be possible to access or modify memberships for a
deleted image. A 404 error will now be returned if a deleted
images' members are accessed or modified.

Fixes: bug #1207266
Co-authored-by: Hirofumi Ichihara <ichihara.hirofumi@lab.ntt.co.jp>

Change-Id: I3e1a7c1cd96b8c85cf0c20286533ced510580492
Merge "Disallow access/modify members of deleted image"