Fix exit status of "service routing start <af> <iface>"

etc/rc.d/routing
	Ignore the exit status of options_{inet,inet6,atm}. It's
	meaningless.

Reviewed by:	hrs
MFC after:	4 weeks
Sponsored by:	Spectra Logic Corp
Differential Revision:	https://reviews.freebsd.org/D6687

etc/rc.d/routing

@@ -90,18 +90,23 @@ routing_stop()
 
 setroutes()
 {
+	local _ret
+	_ret=0
 	case $1 in
 	static)
 		static_$2 add $3
+		_ret=$?
 		;;
 	options)
 		options_$2
 		;;
 	doall)
 		static_$2 add $3
+		_ret=$?
 		options_$2
 		;;
 	esac
+	return $_ret
 }
 
 routing_stop_inet()