Fix the duplicated image params in a test

In _test_create, there is a parameter "no_image" to disable "image_ref"
in a request body of "create a server" API. The way of disabling is
setting '' as "image_ref".
So the unit tests using _test_create pass the duplicated images:
the parameter image_ref '' and the parameter block_device_mapping

This patch fixes this duplicated image parameters.
This problem was detected through the API validation works and
Ic17d2227909c9180ca86c9d578dad4c73ec57dfc needs this fixing.

Change-Id: I36ffc87309afadec7da3fa19e01ea8f00f0f9f8d
live migrate conductor tasks to use nova.image.API

While the patch (I67e7c9d841e5bad82cdca8f7048eaa57f0cfbb2f) was being
reviewed, live_migrate functionality was moved to the conductor. This
live_migrate task code needed to be updated to refer to the new
nova.image.API object instead of the old nova.glance.GlanceImageService
object, which had a slightly different API.

Change-Id: I7ddb778432643f4b5371d11b675951fc678135c5
Closes-bug: #1326926
Make exception handling in get_image_metadata more specific

The generic try/except with Exception was masking an
AttributeError raised during migration flows in conductor.

This change makes the error handling specific to the translated
exceptions raised from the image service in nova.image.glance,
specifically the _translate_image_exception method.

Related-Bug: #1326926

Change-Id: I3e4db73569fc1b02d7a05b4ab10fe83fec956922
Merge "Fix the duplicated image params in a test"