Merge commit '73890a86ef' into maint-0.4.1

tor-github/pr/1283, with the following changes:
* cherry-pick the merge commit in 1283 on top of...
* tor-github/pr/1174, but with the last commit re-worded to remove
    the fixup, because fixups break our push rules.

This is an "ours" merge, except for the bugfix version change in
changes/bug30649.

changes/bug30649

@@ -1,4 +1,4 @@
   o Minor bugfixes (circuit padding):
     - On relays, properly check that a padding machine is absent before
       logging a warn about it being absent. Fixes bug 30649;
-      bugfix on 0.4.1.1-alpha.
+      bugfix on 0.4.0.1-alpha.