Version bump to N2G47Z

Change-Id: I2d634c678f97f7bc7796a2d7e2b3b3a5beb09772
diff --git a/core/build_id.mk b/core/build_id.mk
index a03e781..93a1efb 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -18,4 +18,4 @@
 # (like "CRB01").  It must be a single word, and is
 # capitalized by convention.
 
-export BUILD_ID=N2G47Y
+export BUILD_ID=N2G47Z