Update Security String to 2017-02-01 in klp-dev

Change-Id: I8989e06799d0dc65644abd122f2f1b5cbd5125b7
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index fb18b61..e750b95 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -70,7 +70,7 @@
   # 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 := 2017-01-05
+  PLATFORM_SECURITY_PATCH := 2017-02-01
 endif
 
 ifeq "" "$(PLATFORM_BASE_OS)"