Event var_deref_model: Variable "array_of_integers" tracked as NULL was
passed to a function that dereferences it. [model]
The arrays passed down type_get_contents may be NULL, only iff max_* is 0...
If the max_* parameter does not fit, an error is returned, anyhow.
One could improve the checks of MPI_PARAM_CHECK, but to be on the
safe side, fix in dt_args.c.
This commit was SVN r17974.