#20871: improve email policy test coverage.

More tests of the concrete policy methods would probably be
a good idea, but this is a start, and it brings line coverage
up to 100% for the policy module.

Patch by Milan Oberkirch.
diff --git a/Misc/ACKS b/Misc/ACKS
index 9c559ec..2ed4199 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -951,6 +951,7 @@
 James Oakley
 Elena Oat
 Jon Oberheide
+Milan Oberkirch
 Pascal Oberndoerfer
 Jeffrey Ollie
 Adam Olsen