templates: disk_ks is now version 3
    
    Summary:
    This goes with D968, which bumped the version of the disk_ks
    image, so templates has to stay in sync.
    
    Test Plan:
    As per D968 (you'll need this diff as well or else
    the tests will try to use the wrong disk image).
    
    Reviewers: jskladan, garretraziel
    
    Reviewed By: garretraziel
    
    Subscribers: tflink
    
    Differential Revision: https://phab.qadevel.cloud.fedoraproject.org/D969