Sync common client code from Oslo

Oslo-incubator contains common code for pythonclient - HTTPClient(),
Managers, Exceptions, etc.
We should use common code from Oslo instead of tuskar implementation.

blueprint common-client-library-2

Change-Id: Ie37cd9e024d0360e58b08d60c04ba1024d9afe9c
Use Resource() class from common Olso code

Almost all methods from tuskar Resource() are similar to methods
from common Resource(), so there is a sense to use inheritance to
remove a duplicate methods from Resource() in tuskarclient.

blueprint common-client-library-2
Change-Id: Ibde1730a799b7f94e50d8f5ffb0147102702beba
Merge "Sync common client code from Oslo"
Merge "Use Resource() class from common Olso code"