[python-celery/f15] (3 commits) ...Merge branch 'f16' into f15

[Jon Ciesla]

Summary of changes:

  b5c577f... Revert "2.5.5." (*)
  7da22c4... Merge branch 'f17' into f16 (*)
  02ed1dc... Merge branch 'f16' into f15

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