net: fix socket leak in case of Dial failure
net: fix socket leak in case of Dial failure

Socket descriptors are not closed when fd.connect() fails during generic socket creation.
After a connection failure [ECONNREFUSED] descriptors are left in SYN_SENT state indefinitely (unless they get an explicit RST). Repeated failed connections will eventually cause your program to hit the user/system max-open-files limit.

Fixes issue 2349.

R=golang-dev, mikioh.mikioh
CC=golang-dev
http://codereview.appspot.com/5229047

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang