core: only watch processes when it's really necessary
    
    If we know that main pid is our child then it's unnecessary to watch all
    other processes of a unit since in this case we will get SIGCHLD when the main
    process will exit and will act upon accordingly.
    
    So let's watch all processes only if the main process is not our child since in
    this case we need to detect when the cgroup will become empty in order to
    figure out when the service becomes dead. This is only needed by cgroupv1.
    
    Thanks Renaud Métrich for backporting this to RHEL.
    Resolves: #1744972
    
    patch_name: 0233-core-only-watch-processes-when-it-s-really-necessary.patch
    present_in_specfile: true
    location_in_specfile: 233
    squash_commits: true