namelist_byvar/namelist_* file creation issue

[phillips-ad]

A combined set of directory structure and file naming conditions can lead the CVDP-LE to not see data files.

Two conditions must be met to trigger the bug:
1 - Variable names are at the beginning of the file name. (ex. pr_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc)
2 - All run data for every variable is in one directory.

If those two conditions are met, the CVDP-LE may not see any files in the model run directory.
An example of the problematic structure/file names:
ls /project/CanESM2
pr_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
tas_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
pr_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc
tas_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc
psl_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
ts_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
psl_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc
ts_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc

To allow the CVDP-LE to see the data, the above files should be put into variable directories:
mkdir pr tas psl ts
mv pr_* pr/
mv tas_* tas/
mv psl_* psl/
mv ts_* ts/
ls /
pr/pr_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
tas/tas_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
pr/pr_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc
tas/tas_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc
psl/psl_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
ts/ts_Amon_CanESM2_historical_rcp85_r1i1p1_195001-210012.nc
psl/psl_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc
ts/ts_Amon_CanESM2_historical_rcp85_r2i1p1_195001-210012.nc