Remove openstack-rally entry point

Closes-Bug: #1353233
Change-Id: I5582b1c1942a094ea9486f07d49386106282201c
Refactor Move atomic actions from benchmark scenarios

- Move atomic actions from benchmark/scenario/utils.py
to benchamrk/scenario/base.py
- Removed the scenario_utils imports
- Updated the scenario_base imports and related changes in
all rally files.

Closes-Bug:#1353464
Change-Id: I7f4d3e4b1d3650d97af08e5aca38fa80cc9f6fac
Merge "Refactor Move atomic actions from benchmark scenarios"
Amended sphinx documents

  Updated from https://wiki.openstack.org/wiki/Rally

Change-Id: I520b08202910ad476447fa09ca0a5993fc1bffc5