Clarify sop_pushing_updates for bodhi mega-updates
    
    Previously there was not a clear delineation about the
    responsibility of the RelEng Team Member doing pushes to list each
    build individually for a bodhi update that contained multiple
    N-V-Rs. This pull request makes that more clear.
    
    Signed-off-by: Adam Miller <maxamillion@fedoraproject.org>