Fix the Fedora image download
Fix the Fedora image download

http://cloud.fedoraproject.org/fedora-20.x84_64.qcow2 was redirecting
to a html page.

Change-Id: I773b211d2288c1c9520caf08cbf58d689b94fdb4

rdo-management/tripleo-image-elements,radez/tripleo-image-elements,openstack/tripleo-image-elements,openstack/tripleo-image-elements,rdo-management/tripleo-image-elements,radez/tripleo-image-elements