QtPython: don't quote variables which may be a list

PYTHON_INCLUDE_DIRS may include more than one value which, if quoted,
gives a single include path with a ';' in it.

Change-Id: Ifa4217d92352307dc6a4da23e4b7f1ff4f58fcc6
QtPython: find PythonLibs

Change-Id: I4d0b0a9fd8bc9af5144b7f60f34c4fbf63538c70
Merge topic 'update-vtk-20141030' into next

b2208efe QtPython: find PythonLibs
52b629cf QtPython: don't quote variables which may be a list