Update security string to 2015-12-01 - DO NOT MERGE

Change-Id: I155ec6c2b57c899f20bb85f5a5cf031499ba81b0
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index e405b6d..0b47ac0 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -73,7 +73,7 @@
   # Can be an arbitrary string, but must be a single word.
   #
   # If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
-  PLATFORM_SECURITY_PATCH := 2015-11-01
+  PLATFORM_SECURITY_PATCH := 2015-12-01
 endif
 
 ifeq "" "$(PLATFORM_BASE_OS)"