Update based on code review

main.go

@@ -65,9 +65,7 @@ func usage() {
 func main() {
 	// Create a FlagSet and sets the usage
 	fs := flag.NewFlagSet("nats-server", flag.ExitOnError)
-	fs.Usage = func() {
-		usage()
-	}
+	fs.Usage = usage
 
 	// Configure the options from the flags/config file
 	opts, err := server.ConfigureOptions(fs, os.Args[1:])

server/opts.go

@@ -1014,7 +1014,7 @@ func ConfigureOptions(fs *flag.FlagSet, args []string) (*Options, error) {
 
 	// Process signal control.
 	if signal != "" {
-		if err := processSignal(fs, signal); err != nil {
+		if err := processSignal(signal); err != nil {
 			return nil, err
 		}
 	}
@@ -1157,7 +1157,7 @@ func overrideCluster(opts *Options) error {
 	return nil
 }
 
-func processSignal(fs *flag.FlagSet, signal string) error {
+func processSignal(signal string) error {
 	var (
 		pid           string
 		commandAndPid = strings.Split(signal, "=")