gpg: Skip no-symkey-cache on ubuntu 18.04, gpg version too old

gnupg/gpg.conf.j2

@@ -34,7 +34,12 @@ fixed-list-mode
 no-mangle-dos-filenames
 require-cross-certification
 
+{% if not (distro == 'ubuntu' and ansible_distribution_version == '18.04') -%}
+{# looks like the gpg version in that ubuntu release it too old and does not
+{# contain the setting #}
 # do not cache keys for symmetric encryption
 no-symkey-cache
 
+{% endif -%}
+
 keyserver-options no-honor-keyserver-url no-auto-key-retrieve include-revoked