[gdm] (8 commits) Non-fast-forward update to branch wip/fix-xorg-fallback

[Ray Strode <halfline src gnome org>]

The branch 'wip/fix-xorg-fallback' 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:

  ded34ee... session-worker: don't set PAM_TTY to bogus value on failure
  74af8ec... local-display-factory: don't jump to failed display
  5ca2284... local-display-factory: add some more debug statements

Commits added to the branch:

  3bd4407... local-display-factory: add more debug messages to new vt ha (*)
  e163389... local-display-factory: don't start two greeters at startup (*)
  8169cd4... session-worker: don't switch VTs if we're already on the ri (*)
  846ea87... Merge branch 'wip/fix-double-greeters' into 'master' (*)
  4efc034... session-worker: don't set PAM_TTY to bogus value on failure (*)
  11fe198... Merge branch 'wip/fix-pam-group' into 'master' (*)
  cf8d918... local-display-factory: don't jump to failed display
  4c790bf... local-display-factory: add some more debug statements

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