[Dune] auto-build.

[Christian Engwer]

> I think the errors in common occur because mpi was not found.
> I think this is because now oine has to enable-parallel to get mpi.

If a test requires MPI, then this test is to be disabled if MPI is
not available. If parts of test requires MPI then this part should be
in a conditional.

> I think this should be enabled in the common configure and the errors
> will vanish.

We should also have test building with MPI, but we have to test the
,,basic'' configuration a user will have when building Dune without
fancy stuff.

Christian