New lo_driver.py Incompatible with LROC NAC Images

Hi, myself and @steo85it got this error when trying to use a template csm script (see [here](https://stereopipeline.readthedocs.io/en/latest/examples/csm.html) at section 8.12.2) to convert LRO NAC cub files to jsons (which should not trigger an lo_driver.py call). Both of us have found that when reverting our cloned repos to the 57e0d2a commit this issue goes away and the conversion works. We think this might hint to an issue of the LO driver being called for LRO images. Although reverting to the other commit works, it is not optimal.