Update/add/remove images

* remove Fedora-x86_64-20-20131211.1-sda, Fedora-x86_64-20-20140618-sda
  is already availabe because Heat is enabled
  (https://github.com/openstack-dev/devstack/blob/master/stackrc#L450)
* update version of CirrOS, latest version is 0.3.3
* add current Trusty image (trusty-server-cloudimg-amd64-disk1)

Change-Id: I3dc3a35724fca4fa98559eef275c1b3d818825d9
Merge "Update/add/remove images"