[mate-screensaver/f16] (4 commits) ...Merge branch 'master' into f16

[Dan Mashal]

Summary of changes:

  5a50333... only allow one instance per user, fix dual login prompt (*)
  90ed185... fix release, bump (*)
  c59743d... conditionals to use systemd or CK depending on fedora versi (*)
  01ec965... Merge branch 'master' into f16

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