qemu-iotests: add option in common.qemu for mismatch only

Add option to echo response to QMP / HMP command only on mismatch.

Useful for ignore all normal responses, but catching things like
segfaults.

Signed-off-by: Jeff Cody <jcody@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
1 file changed