Check create from image policy when image not none
Check create from image policy when image not none

This patch fixs the mistake in [1].

[1]: https://review.openstack.org/#/c/511427/4/cinder/volume/api.py
Closes-Bug:1742609

Change-Id: I762ea23ebe37c5286de3cdbf6ff91d4df481ae75

phenoxim/cinder,mahak/cinder,Datera/cinder,openstack/cinder,j-griffith/cinder,phenoxim/cinder,openstack/cinder,mahak/cinder,Datera/cinder,j-griffith/cinder