Allows rescue tests to run using private key auth to instance

Change-Id: I163434dff8bd96a60e244b52f754b843385554fb
Changes verification of a new image to check by id

* Checks if the correct image exists by id only. It's too easy
  for certain properties (server hosted from) to interfere with
  object equality

Change-Id: I500c1f1c577a18dda750ae158d55e0e31d39f740
Merge "Allows rescue tests to run using private key auth to instance"
Merge "Changes verification of a new image to check by id"