ifupdown resolved script has typo

There's another similar typo in the /etc/network/if-up.d/resolved script, on line 71:
```
    if ! cmp --silent "$oldstate" "$newstate" 2>/dev/null; then
        DNS DNS6 DOMAINS DOMAINS6 DEFAULT_ROUTE
        # v4 first
```
Comment it out, as it's not valid code.

Also, on lines 40-45, there's this:
```
    DNS=DNS
    DOMAINS=DOMAINS
    if [ "$ADDRFAM" = "inet6" ]; then
        DNS=DNS6
        DOMAINS=DOMAINS6
    fi
```
Which ends up writing this on lines 94-95:
```
SERVERS=$(echo $DNS6 $DNS)
DOMAINS=$(echo $DOMAINS6 $DOMAINS)
```
Generating this:
```
# cat /run/systemd/resolve/netif/3

# This is private data. Do not parse.
LLMNR=yes
MDNS=no
SERVERS=DNS
DOMAINS=DOMAINS
```
And ultimately ending up here:
```
# grep ^search /etc/resolv.conf

search example.org DOMAINS
```

Oh, and when you run `ifup enp3s0` by hand, you get this error:
```
# ifup enp3s0

ifup: interface enp3s0 already configured

# ifdown enp3s0

# ifup enp3s0

mkdir: missing operand
Try 'mkdir --help' for more information.
```

It looks like this error is from line 26 of /etc/network/if-up.d/resolved:
```
    if [ ! "$ifindex" ]; then
        return
    fi
    # mystatedir=/run/network
    mkdir -p $mystatedir

    statedir=/run/systemd/resolve/netif
    mkdir -p $statedir
    chown systemd-resolve:systemd-resolve $statedir
```
Not sure why mystatedir is commented out, but it looks like that's what's wrong this time.

Whoops, found another bug:

```
# ifup enp2s0

/etc/network/if-up.d/resolved: 1: /run/network/ifupdown-inet-enp2s0: DNS=1.1.1.1: not found
/etc/network/if-up.d/resolved: 2: /run/network/ifupdown-inet-enp2s0: DOMAINS=example.org: not found
Failed to parse DNS server address: DNS
Failed to set DNS configuration: Invalid argument

# cat /run/network/ifupdown-inet-enp2s0

"DNS"="1.1.1.1"
"DOMAINS"="example.org"
```

And that comes from lines 47-51 of /etc/network/if-up.d/resolved:
```
    if [ -n "$NEW_DNS" ]; then
        cat <<EOF >"$mystatedir/ifupdown-${ADDRFAM}-$interface"
"$DNS"="$NEW_DNS"
EOF
        if [ -n "$NEW_DOMAINS" ]; then
            cat <<EOF >>"$mystatedir/ifupdown-${ADDRFAM}-$interface"
"$DOMAINS"="$NEW_DOMAINS"
EOF
```
Basically, the double-quotes around "$DNS" and "$DOMAINS" shouldn't be there, because it's a here-doc.

But this reveals another bug: the variable $DOMAINS is used to hold either "DOMAINS" or "DOMAINS6" in lines 41 or 44, but the actual search domains in line 95.

Has this code ever worked?

My apologies, I neglected to specify these details:

OS: Ubuntu 22.04.2 LTS
Package: ifupdown
Version: 0.8.36+nmu1ubuntu3

It's the latest version of ifupdown for Ubuntu 22.04.2 LTS.

There's a 0.8.36+nmu1ubuntu4 version for later versions of Ubuntu.