Don't use a string exception since it's deprecated

Lib/logging/__init__.py

@@ -64,7 +64,7 @@ _srcfile = os.path.normcase(_srcfile)
 def currentframe():
     """Return the frame object for the caller's stack frame."""
     try:
-        raise 'catch me'
+        raise Exception
     except:
         return sys.exc_traceback.tb_frame.f_back