[DO NOT MERGE] Update Security String to 2017-04-01 for mnc-dev

Bug:35314737
Change-Id: If57391fc4ff5335be4e3988c11e068f9a03f0b76
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 55ccde7..ffd15d4 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -105,7 +105,7 @@
   #  It must match one of the Android Security Patch Level strings of the Public Security Bulletins.
   #
   #  If there is no $PLATFORM_SECURITY_PATCH set, keep it empty.
-  PLATFORM_SECURITY_PATCH := 2017-03-01
+  PLATFORM_SECURITY_PATCH := 2017-04-01
 endif
 
 ifeq "" "$(PLATFORM_BASE_OS)"