DO NOT MERGE: change build id to JB MR1.1

Among other things, this helps monitoring of automated tests, to
properly show which branch the device is running on

Change-Id: I8bb8e3ec347849da44d29ce502b09a593d61ae0e
diff --git a/core/build_id.mk b/core/build_id.mk
index cfff307..09f1779 100644
--- a/core/build_id.mk
+++ b/core/build_id.mk
@@ -23,7 +23,7 @@
 # (like "TC1-RC5").  It must be a single word, and is
 # capitalized by convention.
 #
-BUILD_ID := JB_MR1
+BUILD_ID := JB_MR1.1
 
 # DISPLAY_BUILD_NUMBER should only be set for development branches,
 # If set, the BUILD_NUMBER (cl) is appended to the BUILD_ID for