First create the .ssh directory if it doesn't exist.

[Clewsy]

If no .ssh directory has yet been created, starting autossh throws an error:

touch: /root/.ssh/known_hosts: No such file or directory

Subsequently, the grep command also fails:

grep: /root/.ssh/known_hosts: No such file or directory

This commit will ensure the .ssh directory exists before attempting to touch known_hosts.