User request for subgrid heterogeneity in a gridded history file is silently ignored

I tried to make a history file and didn't get the results I expected. Specifically, I requested PFT-level output in a gridded file:

`user_nl_clm`:
```
hist_empty_htapes = .true.

! h0: daily, PFT, gridded
hist_nhtfrq(1) = -24
hist_dov2xy(1) = .true.
hist_mfilt(1) = 365
hist_type1d_pertape(1) = 'PFTS'
hist_fincl1 = 'GRAINC_TO_FOOD', 'GPP'
hist_fincl1 += 'GRAINC_TO_FOOD_ANN'
```

But I got gridcell-level output:
```
float GPP(time, lat, lon) ;
GPP:long_name = "gross primary production" ;
GPP:units = "gC/m^2/s" ;
GPP:cell_methods = "time: mean" ;
GPP:_FillValue = 1.e+36f ;
GPP:missing_value = 1.e+36f ;
GPP:landunit_mask = "unknown" ;
float GRAINC_TO_FOOD(time, lat, lon) ;
GRAINC_TO_FOOD:long_name = "grain C to food" ;
GRAINC_TO_FOOD:units = "gC/m^2/s" ;
GRAINC_TO_FOOD:cell_methods = "time: mean" ;
GRAINC_TO_FOOD:_FillValue = 1.e+36f ;
GRAINC_TO_FOOD:missing_value = 1.e+36f ;
GRAINC_TO_FOOD:landunit_mask = "unknown" ;
```

If the user requests something that the code can't handle, an error should be thrown during the build-namelist step.