Add changes file for connection_mark_for_close()/connection_mark_and_flush() or_connection_t checking

changes/check_for_orconn_on_close

@@ -0,0 +1,4 @@
+  o Minor bugfixes:
+    - Check for closing an or_connection_t without going through correct
+      channel functions; emit a warning and then call
+      connection_or_close_for_error() so we don't assert as in 7212 and 7267.