Version bump to PPR1.180227.004

Change-Id: Iad8dd2c0a7293b35fffe9dccc8114fabdab72996
diff --git a/core/build_id.mk b/core/build_id.mk
index 6ed5931..82f487a 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=PPR1.180227.003
+export BUILD_ID=PPR1.180227.004