sympa_logo_html_definition is needed if its unsed ansible failed

[yodatak]

sympa_logo_html_definition is present in sympa.conf.j2 so if the variable is unset ansible deploiment failed
i fix it with this in the jinja 2
{% if sympa_logo_html_definition is defined %}
logo_html_definition {{ sympa_logo_html_definition }}
{% endif %}