bugfix: Don't block waiting for socket1 connect.

This patch fixes a bug in Happy Eyeballs where curl would wait for a
connect response from socket1 before checking socket2.

Also, it updates error messages for failed connections, showing the ip
addresses that failed rather than just the host name repeatedly.

Bug: http://curl.haxx.se/mail/lib-2013-10/0236.html
Reported-by: Paul Marks