Switch the server image create command from novaclient to SDK. Use the
SDK versions of test fakes to support fake Server resources. Also,
fetch updated image *after* waiting. If a user requests that we wait
(--wait) for a server image to become active before returning, then we
should probably return the final image. If we don't then the image can
appear to be in a non-active state when it fact it's active. Correct
this by fetching the image after the wait call.
Change-Id: I83a403c035add9ab041ed6d59b5b29e42267f143
9acbd3e105