[gnome-session] (6 commits) Non-fast-forward update to branch wip/benzea/systemd-user-switch

[Benjamin Berg <bberg src gnome org>]

The branch 'wip/benzea/systemd-user-switch' 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:

  78a7dd6... main: Add systemd gnome-session monitoring code for leader
  b51851a... gnome-session-ctl: Add helper binary for systemd targets
  203a492... data: Add systemd user units
  047c816... main: Enable systemd usage
  62248ee... manager: Drop DBus restart as it is handled using systemd
  2cd25cd... system: Remove is_last_session API as it is unused

Commits added to the branch:

  c417cc9... main: Add systemd gnome-session monitoring code for leader
  c85dae4... gnome-session-ctl: Add helper binary for systemd targets
  8191e50... data: Add systemd user units
  dafaae5... main: Enable systemd usage
  907577b... manager: Drop DBus restart as it is handled using systemd
  928cdf2... system: Remove is_last_session API as it is unused