Improve erorr handling around 0080 and 0001 datasets

[trey-stafford]

These datasets produce netcdf files for each day that have groups within for each platform (e.g. a group called F17 for the tbs from F17). Sometimes there is no data for the platform we want data for, but the file still exists.

An OSError is raised if a data file for a day exists but the group we try to access isn't present. The NSIDC-0080 get_nsidc_0001_tbs_from_disk function catches OSError and re-raises as FileNotFoundError, which could be misleading.

The 0080 fetch code does not handle the OSError at all.

Ideally, we wrap the fetch code in a generic exception handler that can re-raise a more appropriate error that client libraries can handle as needed.