When doing a knife ssh call, if a connection to a host is not able
to succeed due to host unreachable or down, the entire call can hang. In
order to prevent this from happening, a new timeout option has been added
to allow a connection timeout to be passed to the underlying SSH call
(see ConnectTimeout setting in http://linux.die.net/man/5/ssh_config)
The timeout setting can be passed in via a command line parameter
(-t or --ssh-timeout) or via a knife config
(Chef::Config[:knife][:ssh_timeout]). The value of the timeout is set
in seconds.