Patch for Symfony 2.6

[ksn135]

An exception has been thrown during the rendering of a template ("Notice: Undefined index: guard") ✗ app/console -V Symfony version 2.6.2-DEV - app/dev/debug

[tortuetorche]

:+1: @ksn135 Thank you for this pull request, I hope it'll be merged as soon as possible.

[tortuetorche]

@yohang The last stable version of Symfony OptionsResolver Component is released since 2014-11-28 and it's not compatible with your component.

If you don't want to merge this pull request, maybe you can lock the version of this symfony component in your composer.json file, like this:

{
 //...
 "require": {
    "php": ">=5.3.0",
    "symfony/options-resolver": ">=2.1,<2.6",
    //...
  }
  //...
}

[yohang]

Thanks for the patch !