This makes it easier for systemd to track it and avoids race conditions such as
this one:
systemd[1]: PID file /run/sshd.pid not readable (yet?) after start.
systemd[1]: Failed to start SSH Daemon.
systemd[1]: Unit sshd.service entered failed state.
systemd[1]: sshd.service holdoff time over, scheduling restart.
systemd[1]: Stopping SSH Daemon...
systemd[1]: Starting SSH Daemon...
sshd[2315]: Server listening on 0.0.0.0 port 22.
sshd[2315]: Server listening on :: port 22.
sshd[2335]: error: Bind to port 22 on 0.0.0.0 failed: Address already in use.
sshd[2335]: error: Bind to port 22 on :: failed: Address already in use.
sshd[2335]: fatal: Cannot bind any address.
systemd[1]: Started SSH Daemon.
03f13a4939