reset version to avoid confusion

Change-Id: I70c0b48a8f653a0f499d3bc6f782d97aed97316e
diff --git a/core/build_id.mk b/core/build_id.mk
index f7d86dd..6240968 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -19,4 +19,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-export BUILD_ID=HRG22B
+export BUILD_ID=HRG21