Allow custom exception level

Author: jupiter

lib/winston/transports/transport.js

@@ -25,6 +25,7 @@ var Transport = exports.Transport = function (options) {
   this.name             = options.name   || this.name;
 
   this.handleExceptions = options.handleExceptions || false;
+  this.exceptionsLevel = options.exceptionsLevel || 'error';
 };
 
 //
@@ -117,5 +118,5 @@ Transport.prototype.logException = function (msg, meta, callback) {
 
   this.once('logged', onLogged);
   this.once('error', onError);
-  this.log('error', msg, meta, function () { });
+  this.log(self.exceptionsLevel, msg, meta, function () { });
 };