Gates initial geometa dimensionality check by discretization.

[kyle-larkin]

The check for the geometa class dimensionality fails when using a single-catchment basin. This check is mostly relevant for regridding the gridded discretization.

NOTE:

This should likely wait until pending changes are merged, and then rebased to those.

Changes

• Gated the dimensionality check in bmi_model.py based on discretization.

Testing

1. Tested simulations with single-catchment basins with and without gating logic.
2. Ran calibration simulation during Hurricane Irene and reviewed output for sanity.
3. Tested messaging by artificially triggering failure.
4. Confirmed that forcing_input.nx_local and forcing_input.ny_local >= 2 (typically by a fair margin) even if wrf_hydro_geo_meta.nx_local and .ny_local == 1.

Todos

• This could potentially be simplified when refactoring bmi_model.py.
• We could confirm gridded and unstructured actually fail when wrf_hydro_geo_meta.nx_local or .ny_local < 2.

[mxkpp]

The change makes sense.