Merge branch 'bug3888'

changes/bug3888

@@ -0,0 +1,4 @@
+  o Minor bugfixes (bufferevents, fix on 0.2.3.1-alpha):
+    - Fix a use-after-free error with per-connection rate-limiting
+      buckets. Fixes bug 3888.
+

src/or/connection.c

@@ -524,6 +524,7 @@ _connection_free(connection_t *conn)
 #ifdef USE_BUFFEREVENTS
   if (conn->type == CONN_TYPE_OR && TO_OR_CONN(conn)->bucket_cfg) {
     ev_token_bucket_cfg_free(TO_OR_CONN(conn)->bucket_cfg);
+    TO_OR_CONN(conn)->bucket_cfg = NULL;
   }
 #endif