message: fix(http): fix another instance of keep-alive busy-looping
diff: @@ -173,9 +173,10 @@ where I: Io,
  // When writing finishes, we need to wake the task up in case there
  // is more reading that can be done, to start a new message.
  match self.state.reading {
  - Reading::Body(..) => return,
  + Reading::Body(..) |
  + Reading::KeepAlive => return,
  Reading::Init |
  - Reading::KeepAlive | Reading::Closed => (),
  + Reading::Closed => (),
  }
  match self.state.writing {
  