security/acme-client: don't lose /var MFS when disabled

We do it elsewhere as well so bring this up to speed.

CC: @fraenki

security/acme-client/Makefile

@@ -1,5 +1,6 @@
 PLUGIN_NAME=		acme-client
 PLUGIN_VERSION=		1.21
+PLUGIN_REVISION=	1
 PLUGIN_COMMENT=		Let's Encrypt client
 PLUGIN_MAINTAINER=	opnsense@moov.de
 PLUGIN_DEPENDS=		acme.sh bind912

security/acme-client/src/opnsense/service/templates/OPNsense/AcmeClient/rc.conf.d

@@ -3,7 +3,7 @@ acme_http_challenge_enable=YES
 acme_http_challenge_conf="/var/etc/lighttpd-acme-challenge.conf"
 acme_http_challenge_pidfile="/var/run/lighttpd-acme-challenge.pid"
 acme_http_challenge_var_script="/usr/local/opnsense/scripts/OPNsense/AcmeClient/setup.sh"
-acme_http_challenge_var_mfs="/var/etc/acme-client"
 {% else %}
 acme_http_challenge_enable=NO
 {% endif %}
+acme_http_challenge_var_mfs="/var/etc/acme-client"