fedora-atomic: Prepare for AH twowek compose run for Fedora 29
    
    We will run twoweek nightly compose for Fedora 29
    Atomic Host so that we can test and release artifacts
    which we are going to ship for first TwoWeek release
    based on F29.
    
    We will continue using AH artifatcs from Fedora-29-updates
    compose for future Two Week releases once they are available
    
    Changes were done by referring to f28 branch and fedora.conf
    from f29
    
    Signed-off-by: Sinny Kumari <sinny@redhat.com>