This patch ports v2 disk_config extension to v2.1.
Unittest code modified to share testing with both v2/v2.1.
API sample file and their tests have been added.
Also added extension point of server resize V3.
Partially implements blueprint v2-on-v3-api
Change-Id: Id2aace8121a310f8c86c6a9cc532bd1074d653c4
c1ae5e0cbd