Update apiclient.base and reuse new functional

Module apiclient.base has several updates in oslo, so we need to sync
latest code to have ability to reuse new functional.

Updates in oslo which related to usage of apiclient.base in heatclient:
- I491f9b54c7074546cf738c6150666bfcc3966a78
- I1db6c12a1f798de7f7fafd0c34fb0ef523610153

Related to bp common-client-library-2

Change-Id: I509d6efb0c8eef87ba2e4aa02ebb44ba149a9860
Remove None for dict.get()

Because If no default value is specified it defaults to None already.

Change-Id: I1ca522c7eebb2171d1a3efd35680ce42b89237b5
Do not use the '+' operation dict_items()

This operation is undefined in Python3, list() must be called first.

Change-Id: I07a9b81a117dfd38e04e1d92533522036f8b0f9f
Merge "Remove None for dict.get()"
Merge "Update apiclient.base and reuse new functional"
Merge "Do not use the '+' operation dict_items()"