Fixes for different compilers.

When building against MPICH, the NAG Fortran compiler doesn't like the "intent" attributes on the MPI interfaces in m_mpif90.F90, because the "real" MPI interfaces don't have any intent. Therefore, I have removed them here.

When using Intel's compiler with bounds-checking enabled, some subscripts in m_AttrVectComms.F90 seem to cause a false positive (and they aren't needed or correct anyway). So I've taken those subscripts off too.

Neither change should impact any other compiler/configuration.