[gnome-session] (5 commits) Non-fast-forward update to branch wip/laney/systemd-user

[Iain Lane <iainl src gnome org>]

The branch 'wip/laney/systemd-user' 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:

  e1a3315... Start GNOME session with systemd
  ee73b40... When there are no required apps (under systemd), let Setenv
  1a52281... Add a gnome-session-systemd binary to launch the session
  67f83bc... Allow RequiredComponents to be skipped and pass this from t
  0ffa050... Add GNOME_SESSION_AUTOSTART_DIR variable to set the autosta

Commits added to the branch:

  092aff0... When there are no required apps (under systemd), let Setenv (*)
  e060bdc... Add GNOME_SESSION_AUTOSTART_DIR variable to set the autosta (*)
  7de7693... Allow RequiredComponents to be skipped (*)
  2c24898... Add a gnome-session-systemd binary to launch the session (*)
  94a2682... Add systemd user units (*)

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