Backport r58149: Clean Release projects as well.
diff --git a/Tools/buildbot/clean.bat b/Tools/buildbot/clean.bat
index 4b94922..19400a9 100644
--- a/Tools/buildbot/clean.bat
+++ b/Tools/buildbot/clean.bat
@@ -3,4 +3,5 @@
 cd PCbuild
 @echo Deleting .pyc/.pyo files ...
 python_d.exe rmpyc.py
+devenv.com /clean Release pcbuild.sln
 devenv.com /clean Debug pcbuild.sln