Updated openstack/openstack
Project: openstack/horizon  652cbcda3be57f949ed3c73e2de48ade0c512419

Make xvfbwrapper import dependent on the selenium imports

It will not be required unless Selenium is also present.

Change-Id: I9da1c596ad68b68c3ce4e8cd215646209dbaebe7
Closes-Bug: #1336243