python-pyqt4: update to version 4.2

fixes unfetchable source.  No further changes.
untested until bug 2442 has been closed.

diff --git a/packages/python/python-pyqt4_4.0.bb b/packages/python/python-pyqt4_4.2.bb
similarity index 100%
rename from packages/python/python-pyqt4_4.0.bb
rename to packages/python/python-pyqt4_4.2.bb