compressed_image_transport: change JPEG quality dynamically

[Victor Lamoine]

Is there a way to change the JPEG compression quality after it has been set-up with the parameters ?
I have not found a way, setting the JPEG quality parameter after the publishing began has no effect.

https://github.com/ros-perception/image_transport_plugins/blob/indigo-devel/compressed_image_transport/src/compressed_publisher.cpp#L107