[Docs] at tutorial step8, Dead link to source of scenario

[Yuki Nishiwaki]

This is document bug.

In this chapter, the link to scenario sample is dead.
https://rally.readthedocs.org/en/latest/tutorial/step_8_discovering_more_benchmark_scenarios.html

So I should change it to available link.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/200799

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/200799
Committed: https://git.openstack.org/cgit/openstack/rally/commit/?id=aeda72d96fd1f9fc27f5bf70b6d2911c6ce1cfbb
Submitter: Jenkins
Branch: master

commit aeda72d96fd1f9fc27f5bf70b6d2911c6ce1cfbb
Author: Yuki Nishiwaki <email address hidden>
Date: Sat Jul 11 15:23:46 2015 +0900

    Change step_8 docs to fix link to sample scenarios

    This patch change dead link for sample scenarios to available link.

    old-link:
     - https://github.com/openstack/rally/tree/master/rally/benchmark/scenarios

    new-link:
     - https://github.com/openstack/rally/tree/master/rally/plugins/openstack/scenarios
     - https://github.com/openstack/rally/tree/master/rally/plugins/common/scenarios

    Change-Id: Ic827563da5f944167efab765bcfecda63d4c08ee
    Closes-Bug: #1473620