Change the Windows buildbot "clean" step to remove
stale .pyc files.
diff --git a/Tools/buildbot/clean.bat b/Tools/buildbot/clean.bat
index d28262e..7e7d713 100644
--- a/Tools/buildbot/clean.bat
+++ b/Tools/buildbot/clean.bat
@@ -1,3 +1,6 @@
 @rem Used by the buildbot "clean" step.
 call "%VS71COMNTOOLS%vsvars32.bat"
-devenv.com /clean Debug PCbuild\pcbuild.sln
+cd PCbuild
+devenv.com /clean Debug pcbuild.sln
+@echo Deleting .pyc/.pyo files ...
+python_d.exe rmpyc.py