Remove NaN values in Prigent dataset

Fixed by first setting _FillValue to NaN, then setting _FillValue to the
original missing value, via:
ncatted -a _FillValue,Z0a,o,d,NaN Prigent_2005_roughness_0.25x0.25_cdf5_c260218.nc
ncatted -a _FillValue,Z0a,o,d,1.e32 Prigent_2005_roughness_0.25x0.25_cdf5_c260218.nc

Partially addresses #3764

Author: billsacks

bld/namelist_files/namelist_defaults_ctsm.xml

@@ -2636,7 +2636,7 @@ lnd/clm2/surfdata_esmf/NEON/ctsm5.4.0/surfdata_1x1_NEON_TOOL_hist_2000_78pfts_c2
 <use_prigent_roughness dust_emis_method="Leung_2023">.true.</use_prigent_roughness>
 <use_prigent_roughness                              >.false.</use_prigent_roughness>
 <stream_fldfilename_prigentroughness
->lnd/clm2/dustemisdata/Prigent_2005_roughness_0.25x0.25_cdf5_c240127.nc</stream_fldfilename_prigentroughness>
+>lnd/clm2/dustemisdata/Prigent_2005_roughness_0.25x0.25_cdf5_c260218.nc</stream_fldfilename_prigentroughness>
 <stream_meshfile_prigentroughness
 >lnd/clm2/dustemisdata/dust_0.25x0.25_ESMFmesh_cdf5_c240222.nc</stream_meshfile_prigentroughness>