install netcdf ^mpich section needs an overhaul

Hi,

thanks for building this tutorial, I found an issue in the Extra query parameters section. This does not work for me with the current releases/v0.15 branch.

• There is no netcdf package, so this should probably be netcdf-c
• Installing netcdf-c results in the following error which I cannot figure out:

==> Installing netcdf-c
==> No binary for netcdf-c found: installing from source
==> Error: AttributeError: 'list' object has no attribute 'directories'

/shared/spack/lib/spack/spack/build_environment.py:862, in child_process:
        859            tb_string = traceback.format_exc()
        860
        861            # build up some context from the offending package so we can
  >>    862            # show that, too.
        863            package_context = get_package_context(tb)
        864
        865            build_log = None

Start with the linked Extra query parameters section in the tutorial and compare its example with the releases/v0.15 branch. Reproduce the netcdf-c installation error, determine the correct package name and working syntax, then update the section so the example installs successfully on the documented branch.