'createImage' server actions was missed for V2.1 API.
This patch converts 'createImage' server action for V2.1 API
The differences between v2 and v3 are described on the wiki page
https://wiki.openstack.org/wiki/NovaAPIv2tov3.
Change-Id: I5490365c72082b1652ddda2fed97c754fceeed22
Closes-Bug: #1367633
Adds api sample tests and api samples for server's actions
Partially implements blueprint v3-api-unittests
Change-Id: I4b420f09f9fc9a7f6fab8dbaeaa9b93631909255
Ghanshyam