iotests: Add test for active mirroring

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Reviewed-by: Alberto Garcia <berto@igalia.com>
Message-id: 20180613181823.13618-15-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
3 files changed