Fix nominal_satellite_subpoint_lon(dim_0) in gridded output

[LeviDPC]

Gridded output netcdf files (for example as created by the make_GLM_grids.py example) contains output that looks like this:

double nominal_satellite_subpoint_lat ;
	nominal_satellite_subpoint_lat:_FillValue = -999. ;
	nominal_satellite_subpoint_lat:long_name = "nominal satellite subpoint latitude (platform latitude)" ;
	nominal_satellite_subpoint_lat:standard_name = "latitude" ;
	nominal_satellite_subpoint_lat:units = "degrees_north" ;
double nominal_satellite_subpoint_lon(dim_0) ;
	nominal_satellite_subpoint_lon:_FillValue = -999. ;
	nominal_satellite_subpoint_lon:long_name = "nominal satellite subpoint longitude (platform longitude)" ;
	nominal_satellite_subpoint_lon:standard_name = "longitude" ;
	nominal_satellite_subpoint_lon:units = "degrees_east" ;

I'm assuming that the (dim_0) is unintentional. This commit from nbearson should fix it.