Merge remote-tracking branch 'remotes/origin/pull/core/378'

plugins/c9.error/error_handler.js

@@ -115,7 +115,7 @@ function plugin(options, imports, register) {
         var accept = req.headers.accept || '';
 
         if (statusCode == 500) {
-            console.error(err && err.stack);
+            console.error(err && (err.stack || err));
             emitter.emit("internalServerError", {
                 err: err,
                 req: req