Removed unused identifiers

Summary: Eslint doesn't like them and me neither.

Reviewed By: danielbuechele

Differential Revision: D14798690

fbshipit-source-id: 5ee7108b9ecfbb05cf2d54cfce68931d16d69a73

static/setup.js

@@ -8,7 +8,6 @@
 const path = require('path');
 const os = require('os');
 const fs = require('fs');
-const {spawn} = require('child_process');
 
 module.exports = function(argv) {
   if (!process.env.ANDROID_HOME) {