Refs #10439 Update FindPyQt.py and FindPyQt4.cmake from kdelibs.

Source https://projects.kde.org/projects/kde/kdelibs/repository/revisions/a7e47438d4e3469dc9df70d613826cb360fc8d19
Merge pull request #55 from mantidproject/feature/10439_findpyqt_cmake_update

Refs #10439 Update FindPyQt.py and FindPyQt4.cmake from kdelibs.