log/syslog: try /var/run/log, for FreeBSD

Fixes #8449.

LGTM=iant
R=golang-codereviews, iant
CC=bradfitz, golang-codereviews
https://golang.org/cl/145600044

src/log/syslog/syslog_unix.go

@@ -16,7 +16,7 @@ import (
 
 func unixSyslog() (conn serverConn, err error) {
 	logTypes := []string{"unixgram", "unix"}
-	logPaths := []string{"/dev/log", "/var/run/syslog"}
+	logPaths := []string{"/dev/log", "/var/run/syslog", "/var/run/log"}
 	for _, network := range logTypes {
 		for _, path := range logPaths {
 			conn, err := net.Dial(network, path)