* server create required --image even when booting the server from a
volume. Change options to require either --image or --volume to
specify the server boot disk. Using --volume currently uses device
'vda' for the block mapping and ignores any other block mappings
given in --block-device-mapping.
* server create and server show are both affected by bug 1378842 where
an excepion was thrown when no image ID was present in the returned
server object, which is the case for a server booted from a volume.
* Fix the remaining assertEqual() order problems in test_server.py
Closes-Bug: 1378842
Closes-Bug: 1383338
Change-Id: I5daebf4e50a765d4920088dfead95b6295af6a4d
2c9d263611