Bug#895748: mpi-default-dev: add riscv64 to list of MPI arches

[Drew Parsons]

On Sun, 2018-04-15 at 18:33 +0200, Manuel A. Fernandez Montecelo wrote:
> 
> > Whether default to openmpi or to mpich, your choice.
> 
> mpich fails due to tests in the current buildd, and although ideally
> we'll work on it and get it properly fixed soon, for riscv64 it'd
> better
> be "openmpi" at the moment -- which is the defalt for almost all
> other
> arches anyway, as you say further down in your message.

Thanks Manuel, that's a good reason for assigning openmpi to the
riscv64 defaults then.

Drew