KeyError if environment PHPFPM_DECORATE_WORKERS_OUTPUT variable do not exist.

[Wolvverine]

If environment PHPFPM_DECORATE_WORKERS_OUTPUT variable do not exist, will be KeyError.

{% if env('PHPFPM_DECORATE_WORKERS_OUTPUT') %}
decorate_workers_output={{ env('PHPFPM_DECORATE_WORKERS_OUTPUT') }}
{% endif %}