message: feat(GUI): blacklist drives with an env var
  We add an environment variable `ETCHER_BLACKLISTED_DRIVES` that allows
  us to filter certain drives from ever showing up in Etcher with comma
  separated device paths, e.g. `/dev/sda,/dev/sdb,/dev/mmcblk0`.
  Closes:
  Change-Type: patch
  Changelog-Entry: Allow blacklisting of drives through and environment
  variable ETCHER_BLACKLISTED_DRIVES.
diff: @@ -47,6 +47,8 @@ const driveScanner = require('./modules/drive-scanner')
  const osDialog = require('./os/dialog')
  const exceptionReporter = require('./modules/exception-reporter')
  +/* eslint-disable lodash/prefer-lodash-method */
  +
  // Enable debug information from all modules that use `debug`
  // See https://github.com/visionmedia/debug#browser-support
  //
  @@ -55,6 +57,16 @@ const exceptionReporter = require('./modules/exception-reporter')
  process.env.DRIVELIST_DEBUG = /drivelist|^\*$/i.test(process.env.DEBUG) ? '1' : ''
  window.localStorage.debug = process.env.DEBUG
  +/**
  + * @summary Environment variable blacklisted drives by path
  + * @type {Array<String>}
  + * @constant
  + * @private
  + */
  +const BLACKLISTED_DRIVES = process.env.ETCHER_BLACKLISTED_DRIVES
  + ? process.env.ETCHER_BLACKLISTED_DRIVES.split(',')
  + : []
  +
  const app = angular.module('Etcher', [
  require('angular-ui-router'),
  require('angular-ui-bootstrap'),
  @@ -209,7 +221,14 @@ app.run(($timeout) => {
  // available drives list has changed, and incorrectly
  // keeps asking the user to "Connect a drive".
  $timeout(() => {
  + if (BLACKLISTED_DRIVES.length) {
  + const allowedDrives = drives.filter((drive) => {
  + return !BLACKLISTED_DRIVES.includes(drive.device)
  + })
  + availableDrives.setDrives(allowedDrives)
  + } else {
  availableDrives.setDrives(drives)
  + }
  })
  })
  