Hash function leads to segfault when passed an invalid object

The new hash function doesn't check to see if the provided object is valid before calculating the hash value. This can be seen in shiboken/libshiboken/basewrapper.cpp at line 754 and demonstrated using the following code:

>>> from PySide import QtCore
>>> import shiboken
>>> a = QtCore.QObject()
>>> b = QtCore.QObject(a)
>>> shiboken.isValid(a)
True
>>> shiboken.isValid(b)
True
>>> del a
>>> shiboken.isValid(b)
False
>>> hash(b)
Segmentation Fault