Fix ROQ scaling checks

It appears that the ROQ check is updating the roq_params values, and as it iterates through ifos, it scales the roq_params each time.

This merge request makes the following changes:

• prevents the roq_params from being altered at any stage
• requires the roq_scale_factor to be passed to the likelihood

Closes bilby_pipe#147 (closed)

@gregory.ashton @colm.talbot