Brian's vendor/ change requires a clean build.

Change-Id: I074fe1ec176dc005adcd79eaf7c91cc3b8d3f54c
diff --git a/core/cleanspec.mk b/core/cleanspec.mk
index 5d399a7..d4a8eed 100644
--- a/core/cleanspec.mk
+++ b/core/cleanspec.mk
@@ -22,7 +22,7 @@
 # IDEALLY, THOSE STEPS SHOULD BE DONE ATOMICALLY.
 # **********************************************************************
 #
-INTERNAL_CLEAN_BUILD_VERSION := 5
+INTERNAL_CLEAN_BUILD_VERSION := 6
 #
 # ***********************************************************************
 # Do not touch INTERNAL_CLEAN_BUILD_VERSION if you've added a clean step!