don't call start callback in onDie (fix #1391)

lib/appium.js

@@ -488,7 +488,7 @@ Appium.prototype.invoke = function(cb) {
         // if we're using the safari launcher app, don't end the session when
         // instruments inevitably crashes out
         if (!this.isSafariLauncherApp) {
-          this.cleanupSession(null, cb);
+          this.cleanupSession();
         }
       }.bind(this);