message: fix: use correct usbbot blob path in appimages
  We use the `app.asar` relative path to read the usbboot blob files
  instead of relative to the normal project root.
  Change-Type: patch
  Changelog-Entry: Use correct usbboot blob path in AppImages.
diff: @@ -23,13 +23,16 @@ const path = require('path')
  const settings = require('../models/settings')
  const SDK = require('../../../sdk')
  const permissions = require('../../../shared/permissions')
  +const packageJSON = require('../../../../package.json')
  /**
  * @summary The Etcher "blobs" directory path
  * @type {String}
  * @constant
  */
  -const BLOBS_DIRECTORY = path.join(__dirname, '..', '..', '..', 'blobs')
  +const BLOBS_DIRECTORY = packageJSON.packageType === 'AppImage'
  + ? 'bin/resources/app.asar/lib/blobs'
  + : path.join(__dirname, '..', '..', '..', 'blobs')
  const scanner = SDK.createScanner({
  blockdevice: {
  