Open MPI: version 1.8.2.

Upgrade Open MPI to version 1.8.2. For a summary of changes, please see
http://www.open-mpi.org/community/lists/announce/2014/08/0063.php

I also simplified the Fortran dependency, as the help message doesn't seem to add useful information.
This changes the option name, so it won't be preserved across an upgrade to this version. That's why it wasn't changed before.