Update Security String to 2016-05-01 in preparation for May 2016 Security OTA

am: 175b7800

* commit '175b7800':
  Update Security String to 2016-05-01 in preparation for May 2016 Security OTA

core/version_defaults.mk

@@ -73,7 +73,7 @@ ifeq "" "$(PLATFORM_SECURITY_PATCH)"
   # 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 := 2016-04-02
+  PLATFORM_SECURITY_PATCH := 2016-05-01
 endif
 
 ifeq "" "$(PLATFORM_BASE_OS)"