fix test_py3kwarns
The fact that this was failing and went unnoticed so long seems like a good argument for being able to enable and disble py3kwarnings through Python.
diff --git a/Lib/plat-mac/applesingle.py b/Lib/plat-mac/applesingle.py
index 0e2cf91..f6c605f 100644
--- a/Lib/plat-mac/applesingle.py
+++ b/Lib/plat-mac/applesingle.py
@@ -2,7 +2,7 @@
"""
from warnings import warnpy3k
-warnpy3k("In 3.x, the applesingle module is removed.")
+warnpy3k("In 3.x, the applesingle module is removed.", stacklevel=2)
import struct
import sys