port nova v2 images related tests into nova v3 part1

This changeset only copies the v2 files into the appropriate v3
directories unchanged. This is being tried in order to make
reviewing of the porting easier as gerrit will display only what
is actually changed for v3 rather than entirely new files.

Partially implements blueprint nova-v3-api-tests

Change-Id: I4355adee713bb217da7f12d4c2fe9b8abf015b05
Add tests for snapshot_metadata

Add tests for snapshot_metadata.

Change-Id: I651200dcdbecf5c4c520e5957ffea3908a4423ef
Merge "Add tests for snapshot_metadata"
Merge "port nova v2 images related tests into nova v3 part1"