if sigs are disabled, actually disable them

src/posts.js

@@ -201,6 +201,7 @@ var async = require('async'),
 				async.parallel({
 					signature: function(next) {
 						if (parseInt(meta.config.disableSignatures, 10) === 1) {
+							userData.signature = '';
 							return next();
 						}
 						postTools.parseSignature(userData, uid, next);