remove N=1 check when decoding a literal field line with name reference

This field is only used to determine if the dynamic table can be used
when this field is re-encoded. Since we currently don't support use of
the dynamic table, the N value is irrelevant.

decoder.go

@@ -196,7 +196,7 @@ func (d *Decoder) parseIndexedHeaderField() error {
 
 func (d *Decoder) parseLiteralHeaderField() error {
 	buf := d.buf
-	if buf[0]&0x20 > 0 || buf[0]&0x10 == 0 {
+	if buf[0]&0x10 == 0 {
 		return errNoDynamicTable
 	}
 	index, buf, err := readVarInt(4, buf)