KeyError happens when response body dosen't contain the key

[Haiwei Xu]

Sometimes the exception returned from server does not contain a resource key, for example HTTPAccepted(202) just returns a notice, which should not be treated as an exception.

But in openstack/resource.py, it is believed that the response body contains resource_key, which will cause a KeyError.

708 @classmethod
709 def update_by_id(cls, session, resource_id, attrs, path_args=None):
710 """Update a remote resource with the given attributes.
......
748
749 if cls.resource_key:
750 resp = resp[cls.resource_key]
751
752 return resp

[Haiwei Xu (xu-haiwei)]

Fix committed in this patch https://review.openstack.org/#/c/208265/