When find_python_module is used in one of our Cmake files and the Python module
that is listed there is missing on the build system the cmake process does not
fail.  Instead it prints out this funny message:

-- Could NOT find PYTHON_INOTIFY (missing:  PYTHON_INOTIFY)
CMake Warning at CMake/FindPythonModule.cmake:102 (message):
  Removed REQUIRED option while looking for python module 'inotify' because
  BUILD_DOCUMENTATION=OFF.  This allows cmake to continue configuring so you
  could make the doc, but building the code might not be possible.
Call Stack (most recent call first):
  LCU/Maintenance/MDB_tools/CMakeLists.txt:13 (find_python_module)

In my opinion this should rathet fail unless(!) BUILD_DOCUMENTATION=ON.