Even the HTTPException is unknown for ceilometer we should set the code
and print it with the details.

Closes-bug: #1626404
Change-Id: Ib244d8822f7a1ebc1b8ec1b95d13b20bbb69ece0
(cherry picked from commit b8a78396b273c23ba7a633d98365a5dfc969b1f2)

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 1b1917ab9b56fe92235ce336d3df3e7a8c1c81d2)

This is in preparation of moving functional tests currently in
tempest in-tree.

No surprises in this change:

* move files
* update the local imports

Same number of tests run, all still pass.

Change-Id: Ibfeac44421c5f36740b1377868f5ec469b2893f5