Adapt specfile, make-rhat-patches, and README to contrib merge
    
    The "rawhide" branch of selinux-policy and selinux-policy-contrib is
    about to be merged together. Update dist-git for this, so that the next
    build can be performed with the new repo structure.
    
    Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>