Fixed - set PyErr when Container.__init__ fails

[ar45]

When container init failed for whatever reason, previously it resulted
in a SystemError: NULL result without error in PyObject_Call
This will now result in a RuntimeError

>>> import lxc
>>> 
>>> c = lxc.Container('aron')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3/dist-packages/lxc/__init__.py", line 157, in __init__
    _lxc.Container.__init__(self, name)
RuntimeError: Container_init:lxc.c:454: error during init for container 'aron'.
>>> 

Signed-off-by: Aron Podrigal aronp@guaranteedplus.com

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[stgraber]

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