several typos on the shell script to perform test

[Bin Zhao]

In page:
https://docs.openstack.org/performance-docs/latest/test_results/reliability/version_1/index.html

At step Perform tests, the shell script is:

    PLUGIN_PATH="${WORK_DIR}/plugins"
    SCENARIOS="random_controller_reboot_factor.json"
    for scenario in SCENARIOS; do
      rally --plugin-paths ${PLUGINS_PATH} task start --tag ${scenario} ${WORK_DR}/scenarios/${scenario}
    done
    task_list="$(rally task list --uuids-only)"
    rally task report --tasks ${task_list} --out=${WORK_DIR}/rally_report.html

PLUGIN_PATH should be PLUGINS_PATH
WORK_DR should be WORK_DIR
SCENARIOS should be ${SCENARIOS}

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/487312

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/487312
Committed: https://git.openstack.org/cgit/openstack/performance-docs/commit/?id=666fc6ae410d2a079f735103805af3d46c21d4e8
Submitter: Jenkins
Branch: master

commit 666fc6ae410d2a079f735103805af3d46c21d4e8
Author: Bin Zhao <email address hidden>
Date: Wed Jul 26 00:39:35 2017 -0700

    Fix the shell script to run reliability test

    There are 3 minor errors in the shell script.
    This change is to fix them to make the script work.

    Change-Id: I610f99c2a3a9a8d224fdd9d49427a9494ccb6161
    Closes-Bug: #1706537