oomd: stop monitoring user-*.slice slices
    
    ... (rhbz#2177722)
    
    Oomd was killing a login session (user-*.slice/session-*.scope).
    
    Quoting https://bugzilla.redhat.com/show_bug.cgi?id=2177722#c21:
    
    > In F37 and prior the config was killing based on swap and pressure
    > on user-*.slice/user@.service. In 7665e1796f915dedbf8e014f0a78f4f576d609bb
    > it was changed to pressure only on system.slice and all slices under
    > user.slice. The relevant point here is that this change now includes
    > user-*.slice/session-*.scope which is the critical session bits
    > you're seeing killed here.
    >
    > That session scope should be omitted. The config that I intended
    > with the initial PR was for all slices under
    > user.slice/user-*.slice/user@.service to be monitored, not for all
    > slices under user.slice.
    
    With the file removed:
    
    $ oomctl | rg Path | sort
      Path: /system.slice
      Path: /user.slice/user-1000.slice/user@1000.service/app.slice
      Path: /user.slice/user-1000.slice/user@1000.service/session.slice