acme: Fix bugs from upstream's change to socat

The upstream acme.sh package changed to using socat instead of netcat;
update the dependencies to reflect this, and pass --listen-v6 when running
in standalone mode (since socat only listens on IPv4 by default).

Also add a missing cleanup call when certificate issuance fails.

Signed-off-by: Toke Høiland-Jørgensen <toke@toke.dk>

net/acme/files/run.sh

@@ -187,7 +187,7 @@ issue_cert()
         acme_args="$acme_args --dns $dns"
     elif [ -z "$webroot" ]; then
         log "Using standalone mode"
-        acme_args="$acme_args --standalone"
+        acme_args="$acme_args --standalone --listen-v6"
     else
         if [ ! -d "$webroot" ]; then
             err "$main_domain: Webroot dir '$webroot' does not exist!"
@@ -211,6 +211,7 @@ issue_cert()
             err "Restoring staging certificate"
             mv "$STATE_DIR/${main_domain}.staging" "$STATE_DIR/${main_domain}"
         fi
+        post_checks
         return 1
     fi