Comment 0 for bug 2017840

This error happens when you try to run ifup or ifdown:

```
# ifdown enp3s0
/etc/network/if-down.d/resolved: 12: mystatedir: not found

# ifup enp3s0
/etc/network/if-up.d/resolved: 12: mystatedir: not found
```

Here's the first lines of that script:
```
# head -n 12 /etc/network/if-up.d/resolved

#!/bin/sh
#
# Script fragment to make ifupdown supply DNS infromation to resolved
#

case "$ADDRFAM" in
    inet|inet6) : ;;
    *) exit 0 ;;
esac

if systemctl is-enabled systemd-resolved > /dev/null 2>&1; then
    mystatedir statedir ifindex interface
```

I'm thinking that the word `local` should appear before `mystatedir` on line 12.
The `shellcheck` command is ok with that line, but only because it's not checking to see if `mystatedir` is an executable in the $PATH.