connect: Try all addresses in first connection attempt

Fixes a bug when all addresses in the first family fail immediately, due
to "Network unreachable" for example, curl would hang and never try the
next address family.

Iterate through all address families when to trying establish the first
connection attempt.

Bug: http://curl.haxx.se/bug/view.cgi?id=1315
Reported-by: Michal Górny and Anthony G. Basile