Update the monasca plugins to mention the dependency on the python-monascaclient

[Kanagaraj Manickam]

currently python-monascaclient is not in the requirements.txt and when user installs heat-engine and try to find the monasca plugins, it will be missing. And user is not aware of this client dependency. so this bug is filed to update the monasca plugins doc string to mention about this client dependency.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/215592

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/215592
Committed: https://git.openstack.org/cgit/openstack/heat/commit/?id=eda40c693b89c201473f287d3a5e6098372fc190
Submitter: Jenkins
Branch: master

commit eda40c693b89c201473f287d3a5e6098372fc190
Author: Kanagaraj Manickam <email address hidden>
Date: Fri Aug 21 17:19:17 2015 +0530

    Updates monasca plugins doc string to install python-monascaclient

    python-monascaclient is not included in the requirements.txt and
    user is recommeneded to install this client manually. so this patch
    updates the doc string for monasca plugins

    Change-Id: Id7f2365dc6dd76a7035200af8c728b9ff2746e4b
    Closes-Bug: #1487381