Fix 'createImage' server actions for V2.1 API

'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
Merge "Fix 'createImage' server actions for V2.1 API"