fix linting errors

lib/6to5/generation/node/parentheses.js

@@ -1,6 +1,5 @@
-var Node = require("./index");
-var t    = require("../../types");
-var _    = require("lodash");
+var t = require("../../types");
+var _ = require("lodash");
 
 var PRECEDENCE = {};
 

lib/6to5/generation/node/whitespace.js

@@ -15,7 +15,7 @@ exports.before = {
       }
     },
 
-    CallExpression: function (node, parent) {
+    CallExpression: function (node) {
       if (t.isFunction(node.callee)) {
         return 1;
       }
@@ -28,7 +28,7 @@ exports.after = {
 
   list: {
     VariableDeclaration: function (node) {
-      return _.map(node.declarations, "init");;
+      return _.map(node.declarations, "init");
     },
 
     ArrayExpression: function (node) {