message: remove obsolete statements
diff: @@ -400,7 +400,7 @@ impl<'a> Virtq<'a> {
  pub fn set_polling_mode(&mut self, value: bool) {
  let mut vqavail = self.avail.borrow_mut();
  - if value == true {
  + if value {
  *vqavail.flags = VRING_AVAIL_F_NO_INTERRUPT;
  } else {
  *vqavail.flags = 0;
  