This change eliminates the `[ERROR] Could not write pidfile: open /var/run/caddy.pid: permission denied` from caddy.log.
The start-stop-daemon writes the file as root so the DAEMONUSER that caddy runs as cannot write to the .pid file.
`$(which setcap)` might evaluate to nothing,
and this way the error thrown will be more clear.
If setcap is not available on Debian/Ubuntu,
you can install the package `libcap2-bin`
* dist/init/linux-sysvinit: pass --oknodo for --start as well
* dist/init/linux-sysvinit: manually rm PIDFILE
Since start-stop-daemon --remove-pidfile is new and not present
everywhere.
