Set BUILD_ID to use MT 2 letter abbreviation.

BUG: 27642720
Change-Id: I2edb8808bfd7433ee630011dd57f7bf9e6ad7ba2
diff --git a/core/build_id.mk b/core/build_id.mk
index 20b88f6..7f0cd6f 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=MHC19N
+export BUILD_ID=MTC74