Add Fedora 20 to IMAGE_URLS

Fedora 20 is only added to IMAGE_URLS if
$HEAT_FETCHED_TEST_IMAGE contains the exact known image name

This image is used for running heat tempest tests which require
an image which has heat-cfntools installed.

Change-Id: Ic6cdea932a5d5f3de138da96d27e407775b3e84b
Merge "Add Fedora 20 to IMAGE_URLS"