title: pssh and known_hosts file
body: <p>when I use pssh, trying to access a remote machine which is not inside the UNIX 
  known hosts file, pssh freeze after giving the password.
  After having added the host using a direct ssh command, pssh works.</p>
  
  <p>So is there an option to give to the pssh command in order to avoid this problem ?</p>
  
  <p>Thanks for your help,
  Regards</p>