Oslo team is recommending everyone to use the direct imports and
not use the Oslo namespaces. So switch all our code to use oslo_*
instead of "from oslo." or "import oslo" or "from oslo"
NOTE: some of the tests still have mocks referring to oslo.utils
@mock.patch('oslo.utils.timeutils.utcnow')
as the tests break otherwise. We should do this later.
Closes-bug: #1419385
Change-Id: I8e3fbeb833cddc3f55674a0e781ffe69d5033ad4
17c5711c55