docs/SECURITY: the max embargo is 14 days now

docs/SECURITY.md

@@ -64,7 +64,7 @@ announcement.
   [distros@openwall](http://oss-security.openwall.org/wiki/mailing-lists/distros)
   when also informing and preparing them for the upcoming public security
   vulnerability announcement - attach the advisory draft for information. Note
-  that 'distros' won't accept an embargo longer than 19 days.
+  that 'distros' won't accept an embargo longer than 14 days.
 
 - Update the "security advisory" with the CVE number.