Fix bug on EStructuralFeature owner assignment on EClass update
Fix bug on EStructuralFeature owner assignment on EClass update

This bug was introducing a bad owner to a feature when an EClass was
updated. The scenario is the following:

>>> A = EClass('A')
>>> a = A()
>>> A.eStructuralFeatures.append(EAttribute('name', EString))
>>> a.name
>>> a.__dict__['name']._owner is a
False  # Issue, it should be True!
>>> a.__dict__['name']._owner is A.python_class
True  # Issue, it should be False!

This commit fixes the issue, the behavior is now the good one:

>>> assert a.__dict__['name']._owner is a

aranega/pyecore,pyecore/pyecore