[mutter] (6 commits) Non-fast-forward update to branch wip/carlosg/xwayland-startup-side-channel

[Carlos Garnacho <carlosg src gnome org>]

The branch 'wip/carlosg/xwayland-startup-side-channel' was changed in a way that was not a fast-forward 
update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  15e2906... core: Use DISPLAY envvar to forward in the launch context
  956e640... wayland: Set up initialization X11 socket
  a0abb9c... wayland: Pass private X connection on GNOME_SETUP_DISPLAY
  b8a93a1... xwayland: Allow setting up maintenance processes

Commits added to the branch:

  90a1eb4... Update Japanese translation (*)
  8427568... Update Japanese translation (*)
  1ca2e99... core: Use DISPLAY envvar to forward in the launch context
  ce0171f... wayland: Set up initialization X11 socket
  2f9338b... wayland: Pass private X connection on GNOME_SETUP_DISPLAY
  6560130... xwayland: Allow setting up maintenance processes

(*) This commit already existed in another branch; no separate mail sent