Skip create from image if no glance deployed

The test should not run if no glance is available, else it
would sadly fail, by throwing an exception like [1].

[1]: http://logs.openstack.org/24/571724/1/check/openstack-ansible-functional-ubuntu-xenial/2b1d2ce/job-output.txt.gz#_2018-06-04_14_40_48_660731

Change-Id: I8f8a912b7b1cc4f491420e64d40f7e3f8bdde0da
diff --git a/cinder_tempest_plugin/api/volume/test_create_from_image.py b/cinder_tempest_plugin/api/volume/test_create_from_image.py
index 12e6c8e..02fbd24 100644
--- a/cinder_tempest_plugin/api/volume/test_create_from_image.py
+++ b/cinder_tempest_plugin/api/volume/test_create_from_image.py
@@ -26,6 +26,8 @@
     @classmethod
     def skip_checks(cls):
         super(VolumeFromImageTest, cls).skip_checks()
+        if not CONF.service_available.glance:
+            raise cls.skipException("Glance service is disabled")
 
     @classmethod
     def create_volume_no_wait(cls, **kwargs):