lint: Fix some ESLint errors in pluginfw

src/static/js/pluginfw/installer.js

@@ -21,15 +21,15 @@ const onAllTasksFinished = () => {
 
 let tasks = 0;
 
-function wrapTaskCb(cb) {
+const wrapTaskCb = (cb) => {
   tasks++;
 
-  return function (...args) {
-    cb && cb.apply(this, args);
+  return (...args) => {
+    cb && cb(...args);
     tasks--;
     if (tasks === 0) onAllTasksFinished();
   };
-}
+};
 
 exports.uninstall = async (pluginName, cb = null) => {
   cb = wrapTaskCb(cb);

src/static/js/pluginfw/plugins.js

@@ -5,9 +5,6 @@ const hooks = require('./hooks');
 const path = require('path');
 const runNpm = require('../../../node/utils/run_npm');
 const tsort = require('./tsort');
-const util = require('util');
-const settings = require('../../../node/utils/Settings');
-
 const pluginUtils = require('./shared');
 const defs = require('./plugin_defs');