+The new version of gnutls introduced this new option which mutt did not
+know about, if the cert is signed with an insecure algorithm (md5) it will
+set a particular bit; if the cert is in the cache of the user we will
+unset all bits so this has to be unset as well
+See http://bugs.mutt.org/3229 and http://bugs.debian.org/514960
+