PhotoCalTask mis-calling Colorterm methods

When I implemented DM-2797 I made a few errors in pipe_tasks:

• PhotoCalTask mis-calls two methods of Colorterm by providing filterName, which is not needed
• ColortermLibrary.getColorterm mis-handles glob expressions (the two arguments to fnmatch.fnmatch are swapped).

We also need a unit test for applying colorterms, but that will require enough work that I have made a separate ticket for it: DM-2918. Meanwhile I have tested my changes by running Dominique's CFHT demo. This proves that the colorterm code runs, but does not prove that the terms are correctly applied.