go.talks/pkg/socket: send compiler output to stderr

R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/7300044
diff --git a/pkg/socket/socket.go b/pkg/socket/socket.go
index 96ede2a..fe01cf4 100644
--- a/pkg/socket/socket.go
+++ b/pkg/socket/socket.go
@@ -152,6 +152,7 @@
 	defer os.Remove(bin)
 	dir, file := filepath.Split(src)
 	cmd := p.cmd(dir, "go", "build", "-o", bin, file)
+	cmd.Stdout = cmd.Stderr // send compiler output to stderr
 	if err := cmd.Run(); err != nil {
 		return err
 	}