IPv4 vs IPv6 selector upon SSHServer initiation

[codfant]

This fixes a but where redhat/centos has IPv6 disabled and "OSError: [Errno 97] Address family not supported by protocol" is presented upon server initiation.

[choppsv1]

So usually binding to :: actually allows connections for both IPv4 and IPv6. This change would then default to only allowing IPv4 connections. Is the problem that we are not handling the errored return and then trying the next value (IPv4)?

[codfant]

If the attribute is over-written when the instance is called, then you can still use IPv6. There should be an exception handler in here to check for the OSError assertion, but it's your call if you want to discard the change. I've had to change this code around a bit for it to work in my environment (though).