Adds disk_format parameter to upload_volume method in volumes client

Adds a third parameter, disk_format, to the upload_volume method of
the volumes client. The parameter is also added to the Tempest
configuration and defaults to "raw" if not set.

Closes-Bug: #1218666
Change-Id: I6c62796161c9219cbd80eb9fecc7fbb0f3a4681a
diff --git a/tempest/api/volume/test_volumes_actions.py b/tempest/api/volume/test_volumes_actions.py
index 960785d..ab75d4d 100644
--- a/tempest/api/volume/test_volumes_actions.py
+++ b/tempest/api/volume/test_volumes_actions.py
@@ -99,7 +99,9 @@
         # there is no way to delete it from Cinder, so we delete it from Glance
         # using the Glance image_client and from Cinder via tearDownClass.
         image_name = rand_name('Image-')
-        resp, body = self.client.upload_volume(self.volume['id'], image_name)
+        resp, body = self.client.upload_volume(self.volume['id'],
+                                               image_name,
+                                               self.config.volume.disk_format)
         image_id = body["image_id"]
         self.addCleanup(self.image_client.delete_image, image_id)
         self.assertEqual(202, resp.status)