proper variable used

frontend-js/src/main/js/plugin/Plugin.js

@@ -227,7 +227,7 @@ Plugin.prototype.unload = function () {
     if (validPlugin) {
       return self.getLoadedPluginData().unregister();
     }
-  }).catch(function (e) {
+  }).catch(function (error) {
     GuiConnector.warn("Plugin crashed on upload.");
     if (typeof self.getLoadedPluginData().notifyError === "function") {
       self.getLoadedPluginData().notifyError({error: error});