Bug#1007830: opm-grid: FindMETIS.cmake

[Markus Blatt]

Some explanations:

The autopkgtest of opm-grid creates a DUNE module using duneproject and tries
to build that. This is done to make sure that opm-grid can be used by other
DUNE modules as a DUNE module. Even though opm-grid ships its own 
FindMETIS.cmake test the test in autopkgtest should actually use the one from
  dune-common (/usr/share/dune/cmake/modules/FindMETIS.cmake) and hence exhibit
a bug there (just opened one a few minutes ago). Having said that, it seems 
quite likely that FindMETIS.cmake in opm-grid
(/usr/share/dune/cmake/Modules/FindMETIS.cmake) might have the same problem
and this problem will surface when rebuilding opm-simulators and opm-upscaling.

METIS code is used in opm-simulators via usage of source code of dune-istl.
The reason why opm-grid search for METIS is that Zoltan from trilinos might need
it if a static library of thise is used. Then another user module using opm-grid
will need METIS.