qemu-iotests: Use -nographic in 182

This avoids that random UI frontend error messages end up in the output.
In particular, we were seeing this line in CI error logs:

+Unable to init server: Could not connect: Connection refused

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Kashyap Chamarthy <kchamart@redhat.com>
Reviewed-by: Jeff Cody <jcody@redhat.com>
1 file changed