Refactor: Enclose ZIP generation in try/finally
Refactor: Enclose ZIP generation in try/finally

This ensures that the temporary directory is deleted in
all cases, even if there is an error during ZIP file generation
for both the shapefile and the worksheet, and doesn't leave
any dangling files.

WikiWatershed/model-my-watershed,WikiWatershed/model-my-watershed,WikiWatershed/model-my-watershed,WikiWatershed/model-my-watershed,WikiWatershed/model-my-watershed