Trim down BUILD_FINGERPRINT.

Bug: 15593959
Change-Id: I90161045b5d5f2df726a4f69740f0875c8bfc69f
diff --git a/core/build_id.mk b/core/build_id.mk
index aaf4185..f94b224 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 := OPENMASTER
+BUILD_ID := AOSP
 
 DISPLAY_BUILD_NUMBER := true