serve nfs: unify the nfs library logging with rclone's logging better

Before this we ignored the logging levels and logged everything as
debug. This will obey the rclone logging flags and log at the correct
level.

cmd/serve/nfs/server.go

@@ -37,7 +37,7 @@ func NewServer(ctx context.Context, vfs *vfs.VFS, opt *Options) (s *Server, err
 		ctx: ctx,
 		opt: *opt,
 	}
-	s.handler, err = NewHandler(vfs, opt)
+	s.handler, err = NewHandler(ctx, vfs, opt)
 	if err != nil {
 		return nil, fmt.Errorf("failed to make NFS handler: %w", err)
 	}