fedora-atomic: add in override for vagrant sync location
    
    Go ahead and update the fedora-atomic.conf so that when it gets
    branched it will have the override already in there.
    
    Signed-off-by: Dusty Mabe <dusty@dustymabe.com>
    (cherry picked from commit b69707bdd72f5b4d8ebcbd7ad7ec97fa21b58c79)