aio: remove process_queue callback and qemu_aio_process_queue

Both unused after the previous patch.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
diff --git a/block/rbd.c b/block/rbd.c
index 46a8579..6cd8448 100644
--- a/block/rbd.c
+++ b/block/rbd.c
@@ -504,7 +504,7 @@
     fcntl(s->fds[0], F_SETFL, O_NONBLOCK);
     fcntl(s->fds[1], F_SETFL, O_NONBLOCK);
     qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], qemu_rbd_aio_event_reader,
-                            NULL, qemu_rbd_aio_flush_cb, NULL, s);
+                            NULL, qemu_rbd_aio_flush_cb, s);
 
 
     return 0;
@@ -525,8 +525,7 @@
 
     close(s->fds[0]);
     close(s->fds[1]);
-    qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], NULL , NULL, NULL, NULL,
-        NULL);
+    qemu_aio_set_fd_handler(s->fds[RBD_FD_READ], NULL, NULL, NULL, NULL);
 
     rbd_close(s->image);
     rados_ioctx_destroy(s->io_ctx);