Bug#1121356: opm-simulators FTBFS with scotch 7.0.10

[Drew Parsons]

Source: opm-simulators
Followup-For: Bug #1121356
Control: tags -1 ftbfs

The scotch test failure on ppc64el is Bug#1121516.
Upstream is looking into the problem.

While they're doing that, it'd be great if opm-grid can be updated for
so opm-simulators can pass.

Let me know if you need anything changed in scotch to get opm working,
but in principle its build environment should work the same before.
The changes were mainly with the 64-bit packages, the default package
(32-bit integers) is supposed to respond the same as before.

scotch cmake config files are now available. I think opm-grid wasn't
relying on them to find scotch, but maybe the behaviour changed now
that they are available.  I can't find the definition of
find_package_deps() used in opm-grid-prereqs.cmake.

Once open-grid and opm-simulators, scotch can be hacked to skip its
ppc64el failure if necessary while upstream investigates.