Updated openstack/openstack
Project: openstack/requirements  8f4e4f272f3ce8028325be44e399fc0bf8eda95f

Add xvfbwrapper package for running Selenium tests headless

  - The requirement is related with an issue from Horizon project
  - The requirement needs the xvfb library installed

Change-Id: I93220d23a6838d0c29d264bfd683ee4693137c54