Change build id to OPENMASTER

Change-Id: I2ca9b8de815c9c9e7e9d4c5a616e4ae270992761
diff --git a/core/build_id.mk b/core/build_id.mk
index 64ad133..aaf4185 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,6 +18,6 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-BUILD_ID := KK
+BUILD_ID := OPENMASTER
 
 DISPLAY_BUILD_NUMBER := true