security(data-types): force non-buffer blob values to string, https://github.com…

…/nodejs/node/issues/4660

lib/data-types.js

@@ -578,7 +578,7 @@ BLOB.prototype.validate = function(value) {
 BLOB.prototype.escape = false;
 BLOB.prototype.$stringify = function (value) {
   if (!Buffer.isBuffer(value)) {
-    value = new Buffer(value);
+    value = new Buffer(value.toString());
   }
   var hex = value.toString('hex');