Google moved the Google Drive Icon Helper

Awesome! Thanks for the pull request. Would you mind changing this line to what I have below? This is so that this script will continue to work for all versions (not that it's likely anyone will want to install an older version, but just in case).

```Ruby
icon_helper = ['/Applications/Google Drive.app/Contents/Helpers/Google Drive Icon Helper', '/Applications/Google Drive.app/Contents/Resources/Google Drive Icon Helper'].collect do |file|
  file if File.exist? file
end.compact.first
```