make Random shuffle work with both Python 2.7.5 and 2.7.6

2.7.6 changed the API for shuffle(), released in November 2013.

This fix may change the minimal python version needed (currently 2.6.0).
But since I do not have anything older than 2.7.5 installed, it is
difficult to tell. I checked the history of python lib random.py
and there _should_ be no problem.

People installing KDE/4.12 should already have some recent python,
so it should not matter. Anyway this is why I will not backport
this fix to KDE/4.11. And since 4.12.2 is about being released, I put
this fix into 4.12.3

BUG: 330675
FIXED-IN: 4.12.3