Sync Oslo's apiclient

Oslo's version of apiclient fixes a bug where if `human_id` is `None` it
causes `novaclient` to crash, so lets sync it over to fix that bug.

Change-Id: I53f174a1d3356c4038dcbdf88f4f9c4ea179418c
References-Bug: 1288397
Merge "Sync Oslo's apiclient"