undo CL 92210044 / 5cb21eee2d35
undo CL 92210044 / 5cb21eee2d35

<enter reason for undo>

««« original CL description
net: make use of SO_LINGER_SEC on darwin

Fixes issue 7971.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://codereview.appspot.com/92210044
»»»

TBR=iant
R=golang-codereviews
CC=golang-codereviews
https://codereview.appspot.com/96220049

wesolows/golang,wesolows/golang,firebitsbr/golang-old,firebitsbr/golang-old,wesolows/golang-old,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,wesolows/golang-old,firebitsbr/golang-old,wesolows/golang,firebitsbr/golang-old,wesolows/golang,wesolows/golang,wesolows/golang-old,wesolows/golang,wesolows/golang-old,wesolows/golang-old,wesolows/golang-old,firebitsbr/golang-old,firebitsbr/golang-old,firebitsbr/golang-old