netcdf-c

Github issue: https://github.com/Unidata/netcdf-c/issues/206
Re e-eupport VGQ-678069
It was noticed that an attribute value of "nan." was being treated as
legal (it should be "nan"). The reason is that sscanf was not be checked
to see that all the attribute value characters were being read.
Solution is to verify that all characters were being consumed.