The novaclient.v2.images module is deprecated and will be removed
after Nova 15.0.0 is released so we need to migrate to glanceclient.
note: glanceclient doesn't have any Image class. It have image json
schema and use it to generate warlock models when creates image
object.
closes-bug: 1573595
Depends-on: I2e13867bed72fd2ae6749491dd5b032c2c08f9f6
Change-Id: Ie0f04c15e6e49e8e7c77f7b7d870a368cdd5c7c7