Disabled linter on field 'dataref'

Signed-off-by: Benjamin Wang <wachao@vmware.com>

db.go

@@ -129,6 +129,9 @@ type DB struct {
 	path     string
 	openFile func(string, int, os.FileMode) (*os.File, error)
 	file     *os.File
+	// `dataref` isn't used at all on Windows, and the golangci-lint
+	// always fails on Windows platform.
+	//nolint
 	dataref  []byte // mmap'ed readonly, write throws SEGV
 	data     *[maxMapSize]byte
 	datasz   int