Add unregister_image(id) call

Change-Id: Ic2e2a49e7c3f59093d9b68b66948520ed18571a3
Fixes: bug #1237939

AUTHORS

@@ -2,6 +2,7 @@ Alexander Ignatov <aignatov@mirantis.com>
 Alexander Kuznetsov <akuznetsov@mirantis.com>
 Chad Roberts <croberts@redhat.com>
 Jeremy Stanley <fungi@yuggoth.org>
+Matthew Farrellee <matt@redhat.com>
 Nikita Konovalov <nkonovalov@mirantis.com>
 Nikolay Mahotkin <nmakhotkin@mirantis.com>
 OpenStack Jenkins <jenkins@openstack.org>

savannaclient/api/images.py

@@ -34,6 +34,9 @@ class ImageManager(base.ResourceManager):
     def get(self, id):
         return self._get('/images/%s' % id, 'image')
 
+    def unregister_image(self, image_id):
+        self._delete('/images/%s' % image_id)
+
     def update_image(self, image_id, user_name, desc):
         body = {"username": user_name,
                 "description": desc}