Add a sub command to make it easier to manage flavors in plans

[Dougal Matthews]

It is hard to assign flavors with the plan-patch command. You need to do something like:

    tuskar plan-show overcloud | grep "::Flavor" -A 1
    tuskar plan-patch -A compute-1::Flavor=baremetal $PLAN_ID

A new command to make it easier might look something like this:

    tuskar plan-flavors-list $PLAN_ID
    tuskar plan-flavors-update --role compute --flavor baremetal

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/162061

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/162061
Committed: https://git.openstack.org/cgit/openstack/python-tuskarclient/commit/?id=71d9dab436a1c908b890d421e53ddd0679b5f0d4
Submitter: Jenkins
Branch: master

commit 71d9dab436a1c908b890d421e53ddd0679b5f0d4
Author: Marek Aufart <email address hidden>
Date: Thu Mar 5 16:05:36 2015 +0100

    Add Plan Role-Flavors manage methods

    To make easier assigning flavors to roles in a plan from CLI, commands tuskar
    plan-show-flavors and plan-flavor were added.

    Common code with plan-scale was extracted to separated methods.

    Already existing scaling methods by patching plan's parameters were kept.

    Change-Id: I59b99bc16cc4bb4eacefc242b5327944d9049d69
    Closes-Bug: 1422591