There were warnings generated during the build due to missing
attributes, like this:
keystoneclient.rst:7: WARNING: missing attribute mentioned in
:members: or __all__: module keystoneclient.__init__, attribute
v2_0
This is fixed by importing the symbol in __init__.
Closes-Bug: #1315523
Change-Id: I565c78ef8910353c4e1ce1641b42fba7cdbd77d8