SessionClient uses requests library. It's response class doesn't have
"status" property[1], so in case of any errors(with status code > 400),
from_response method is called and raises AttributeError.
Also, HTTPClient implementation uses requests lib by default[2](if 'http'
argument was not transmitted), so from_response method will raise
AttributeError too.
[1] - http://docs.python-requests.org/en/master/api/#requests.Response.status_code
[2] - https://github.com/openstack/python-ceilometerclient/blob/2.6.0/ceilometerclient/openstack/common/apiclient/client.py#L99-L100
Change-Id: Id8fb2f386e8101951716f30a6365c9aa15bd4b24
Closes-Bug: #1620974
(cherry picked from commit 1b1917ab9b)