windows: remove unreachable return statement in Proc.Call
windows: remove unreachable return statement in Proc.Call

Change-Id: I5bb10469bab144f5e42c7bcf6ee8717d3fd0d4e4
Reviewed-on: https://go-review.googlesource.com/47337
Reviewed-by: Matt Layher <76528ff2e917253aa2211f68e4ca60b5b846dcf5@gmail.com>
Run-TryBot: Matt Layher <76528ff2e917253aa2211f68e4ca60b5b846dcf5@gmail.com>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

golang/sys,golang/sys,multiplay/golang-sys,golang/sys,multiplay/golang-sys,multiplay/golang-sys,multiplay/golang-sys