Create needed directory for UsePrivilegeSeparation option

[amontalban]

This PR creates the directory needed when you enable UsePrivilegeSeparation option in SSHD. Otherwise you get this error:

----------
           ID: sshd_config
     Function: file.managed
         Name: /etc/ssh/sshd_config
       Result: False
      Comment: check_cmd execution failed
        Missing privilege separation directory: /var/run/sshd
      Started: 17:35:04.465617
     Duration: 200.223 ms
      Changes:   
 ----------
           ID: openssh
     Function: service.running
         Name: ssh
       Result: False
      Comment: One or more requisite failed: openssh.config.sshd_config
      Changes:   
 ----------

[alxwr]

LGTM Thanks!