engines/libaio: fallback to old io_setup() system call

We can't rely on the new one being there, if we fail calling
io_setup2(), fallback to io_setup() like before.

Fixes: a1b006fe1cd3 ("engines/libaio: fix new aio poll API")
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 file changed