Merge changes from topic 'revert-revert-pipe'

* changes:
  Revert "Revert "Qemu: make the qemu_pipe_open back compatible""
  Revert "Revert "Emulator: Enhance qemu_pipe.h to handle partial rw""
  Revert "Revert "Qemu-pipe: refactor qemu_pipe.h into libqemu_pipe""