Fixed a comment: SECURITY_PATCH corrected to PLATFORM_SECURITY_PATCH

Change-Id: Id4eeaedac02900df7e635f378b54c2e58e9b5c6e
diff --git a/core/version_defaults.mk b/core/version_defaults.mk
index 5178a10..6a0e22c 100644
--- a/core/version_defaults.mk
+++ b/core/version_defaults.mk
@@ -25,7 +25,7 @@
 #     BUILD_ID
 #     BUILD_NUMBER
 #     BUILD_DATETIME
-#     SECURITY_PATCH
+#     PLATFORM_SECURITY_PATCH
 #
 
 # Look for an optional file containing overrides of the defaults,