As indicated in the MPI3.2 document 14.3.10 page 599 line 1, the only
MPI error code possible is MPI_SUCCESS. All other errors must be in the
error class MPI_T_ERR*.
Fix the return of few pvar/cvar function that failed to correctly
convert to an MPI error code.
Signed-off-by: George Bosilca <bosilca@icl.utk.edu>
