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
1 file changed