Minor comment (for prev checkin: 2764).

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2765 ba6dc0ae-232f-0410-883f-9ebac64fc565
Sock: Open restore sockets iff pending incoming.

This prevents us from trying to open IPv6 socks on systems that don't
support the protocol.

git-svn-id: svn://svn.code.sf.net/p/dmtcp/code/trunk@2766 ba6dc0ae-232f-0410-883f-9ebac64fc565