netcdf-c

Replace NC_MAX_DIMS with correct NC_MAX_VAR_DIMS 

The constant NC_MAX_DIMS is used to dimension the `dimids` arrays which are use to retrieve the dimension ids corresponding to the variables dimensions.  By definition, the maximum number of dimension ids is `NC_MAX_VAR_DIMS` as is documented in the `nc_inq_var` documentation:
http://www.unidata.ucar.edu/software/netcdf/netcdf-4/newdocs/netcdf-c/nc_005finq_005fvar.html

dimids   Returned vector of *ndimsp dimension IDs corresponding to the variable dimensions. The caller must allocate enough space for a vector of at least *ndimsp integers to be returned. The maximum possible number of dimensions for a variable is given by the predefined constant NC_MAX_VAR_DIMS. 

Although the default or standard values of NC_MAX_DIMS and NC_MAX_VAR_DIMS are the same, the correct value to be used here is NC_MAX_VAR_DIMS and not NC_MAX_DIMS.  Even though this currently works, it could fail if either NC_MAX_VAR_DIMS or NC_MAX_DIMS is changed and it can also provide an incorrect function usage example that may mislead developers trying to determine the correct usage of the function.