add more ControlPath recommendations to ssh_config.5

[Petr Lautrbach]

Hello,

Right now, there is a recommendation about using special strings in ControlPatch in ssh_config.5,
but there's no specification of recommended directory. So users use random paths like
/home/misc/tmp/%r@%h:%p. Would it be worth to suggest the ~/.ssh/ directory for ControlPath
and to mention that used directory should not be publicly accessible?

It would help to better specify the SElinux policy based on these suggestions [1]

[1] https://bugzilla.redhat.com/show_bug.cgi?id=987554

Thanks,


Petr