Fix firewall rule on BSD

Author: zhxie

internal/exec/firewall_bsd.go

@@ -36,10 +36,7 @@ func addSpecificFirewallRule(ip net.IP, port uint16) error {
 	}
 
 	routeCmd = exec.Command("pfctl", "-d")
-	_, err = routeCmd.CombinedOutput()
-	if err != nil {
-		return fmt.Errorf("exec: %w", err)
-	}
+	_, _ = routeCmd.CombinedOutput()
 
 	routeCmd = exec.Command("pfctl", "-e")
 	_, err = routeCmd.CombinedOutput()