Version bump to PPR1.180131.002

Change-Id: I13c2951367b79f0b20b20bb73fc57fcd2c38229b
diff --git a/core/build_id.mk b/core/build_id.mk
index da49c5e..19e81b1 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=PPR1.180131.001
+export BUILD_ID=PPR1.180131.002