Explicitely find PythonLibs 3.4

cmake 2.8.x supports only up to PythonLibs 3.3 but Maui has 3.4,
so it doesn't find it.

Ask for 3.4 to force FindPythonLibs.cmake to ask for 3.4.

[rpm] Check for PythonLibs 3.4 since it's what Maui provides