grenade: do not use the removed glance v1 API

glance v1 API has been disabled by default in DevStack before Pike:
https://review.openstack.org/#/c/343129/

Change-Id: Ia76ca3422673eec251b5c6076cf26056e0008a69
(cherry picked from commit cfecd605b1)

devstack/upgrade/resources.sh

@@ -77,7 +77,7 @@ function create_flavor {
 }
 
 function register_image {
-    eval $(openstack --os-image-api-version 1 image show \
+    eval $(openstack image show \
             -f shell -c id $SAHARA_IMAGE_NAME)
     resource_save sahara image_id $id
     openstack dataprocessing image register $id --username $SAHARA_IMAGE_USER