fix the log output when data-path is not exist or in use by another instance of nsqd

Author: mdh67899

internal/dirlock/dirlock.go

@@ -27,7 +27,7 @@ func (l *DirLock) Lock() error {
 	l.f = f
 	err = syscall.Flock(int(f.Fd()), syscall.LOCK_EX|syscall.LOCK_NB)
 	if err != nil {
-		return fmt.Errorf("cannot flock directory %s - %s", l.dir, err)
+		return fmt.Errorf("cannot flock directory %s - %s (possibly in use by another instance of nsqd)", l.dir, err)
 	}
 	return nil
 }

nsqd/nsqd.go

@@ -108,7 +108,7 @@ func New(opts *Options) (*NSQD, error) {
 
 	err = n.dl.Lock()
 	if err != nil {
-		return nil, fmt.Errorf("--data-path=%s in use (possibly by another instance of nsqd)", dataPath)
+		return nil, fmt.Errorf("failed to lock data-path: %v", err)
 	}
 
 	if opts.MaxDeflateLevel < 1 || opts.MaxDeflateLevel > 9 {