last handler for undefined in models/comment.js

lib/models/comment.js

@@ -29,7 +29,7 @@ module.exports = function(crowi) {
       newComment.revision = revisionId;
       newComment.comment = comment;
       newComment.commentPosition = position;
-      newComment.isMarkdown = isMarkdown;
+      newComment.isMarkdown = isMarkdown || false;
 
       newComment.save(function(err, data) {
         if (err) {