Merge remote-tracking branch 'origin/maint-0.2.2'

Conflicts:
	src/or/connection_or.c

The conflict in src/or/connection_or.c is resolved by taking the
version in master, since e27a26d5 already fixed bug 4531 on master.
This merge just adds the changes file from 0.2.2.

changes/bug4531

@@ -0,0 +1,4 @@
+  o Major bugfixes:
+    - Fix null-pointer access that could occur if TLS allocation failed.
+      Fixes bug 4531; bugfix on 0.2.0.20-rc. Found by "troll_un".
+