SNMP ACL - optional field

geant/gap_ansible/roles/bc_templates/routers/nokia/system/security/snmp.j2

@@ -20,7 +20,9 @@
           {% endif %}
             <access-permissions>r</access-permissions>
             <version>{{ community.version | default('v2c') }}</version>
+            {% if community.acl_name is defined %}
             <source-access-list>{{ community.acl_name }}</source-access-list>
+            {% endif %}
           </community>
         {% endfor %}