[Paraview] python mismatch with superbuild on os x

[Ben Boeckel]

On Thu, Jan 25, 2018 at 11:40:40 +0100, Nicolas Vuaille wrote:
> I don't know if there is a proper fix but there is a CMake option to bypass
> this check:
>  set PYTHON_I_KNOW_WHAT_IM_DOING to true may solve the problem.

Indeed, this is the workaround. The problem is that we've had folks with
Homebrew Python where we end up finding `/usr/bin/python`, the library
from the SDK, and the headers from Homebrew. This, to say the least,
tends not to work out too well. However, you usually don't know until
your `pvpython` ends up busted, so instead we put the logic in the
superbuild. That escape hatch is there to avoid the check, but you
really should be using Python bits which agree on their version.

--Ben