aio / timers: remove dummy_io_handler_flush from tests/test-aio.c

Remove dummy_io_handler_flush from tests/test-aio.c as it does
nothing now.

Signed-off-by: Alex Bligh <alex@alex.org.uk>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
aio-win32: replace incorrect AioHandler->opaque usage with ->e

The AioHandler->opaque field does not exist in aio-win32.c.  The code
that uses it was incorrectly copied from aio-posix.c.  For Windows we
can use AioHandler->e to match against AioContext->notifier.

This patch fixes the Windows build for aio-win32.o.

Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
win32-aio: drop win32_aio_flush_cb()

The io_flush argument to qemu_aio_set_event_notifier() has been removed
since the block layer learnt to drain requests by itself.  Fix the
Windows build for win32-aio.o by updating the
qemu_aio_set_event_notifier() call and dropping win32_aio_flush_cb().

Reviewed-by: Stefan Weil <sw@weilnetz.de>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>