Use common "waiters.wait_for_image_status" function everywhere

In Tempest we have the waiters.wait_for_image_status function that
is already used in some places. So this commit replaces the use of the
wait_for_image_status method defined in the images_client.py file with
the use of the waiters.wait_for_image_status function.

Change-Id: If42cfbfa1f7dae5af276e80f38f6294ced00ac5b
10 files changed