Global variables in plugin should be moved to plugin settings

[Victor Ryzhenkin]

Now murano global variables for devstack exists in plugin.sh . This is not good.
Need to move definitions of these variables to plugin settings.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/239779

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/239779
Committed: https://git.openstack.org/cgit/openstack/murano/commit/?id=3984c1ba4640a719ce9ad207f383f43b7861c9db
Submitter: Jenkins
Branch: master

commit 3984c1ba4640a719ce9ad207f383f43b7861c9db
Author: Victor Ryzhenkin <email address hidden>
Date: Wed Oct 28 04:08:43 2015 +0300

    Move variables from plugin.sh to settings

    Global variables are the same as settings and should be
    in plugin settings file.
    This patch moves variables from plugin.sh to settings file.
    Also add a few comments for variables groups for better understanding
    for what specific variable is responsible.

    Change-Id: I47aef3b047ce11a5729643353e801eee963e4e76
    Closes-Bug: #1510744