for specifying Boolean values, allow True, true, 1, on

[Ruby Loo]

The valid input strings for Boolean values is inconsistent among the subcommands. eg:
- for node-set-console-mode: 'true', 'false'
- for node-set-maintenance: 'on', 'off', (and 'true', 'false', 'True', 'False' with https://review.openstack.org/150692
- node-list, --maintenance, --associated: 'true', 'false', 'True', 'False'

We should allow the same set of valid values for all of them.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/170230

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/170230
Committed: https://git.openstack.org/cgit/openstack/python-ironicclient/commit/?id=8fd2ac3ba1c48189d60d73043c4b6868de2633f2
Submitter: Jenkins
Branch: master

commit 8fd2ac3ba1c48189d60d73043c4b6868de2633f2
Author: Ruby Loo <email address hidden>
Date: Thu Apr 2 18:17:33 2015 +0000

    Consistent and more valid strings for Booleans

    The set of valid input strings for Boolean values was inconsistent among
    the subcommands of the Ironic CLI. egs:
     -for node-set-console-mode: 'true', 'false'
     -for node-set-maintenance: 'on', 'off', 'true', 'false', 'True', 'False'

    This change allows the same set of valid values for all the subcommands:
    '0', '1', 'f', 'false', 'n', 'no', 'off', 'on', 't', 'true', 'y', 'yes'.

    For invalid strings, we output the subcommand usage along with the
    argument, invalid string, and valid string choices.

    At the API level, if NodeManager.set_maintenance() is passed an invalid
    state (maintenance mode) value, an InvalidAttribute exception is raised.

    Change-Id: I541695388489cdc640265df8ee6a9999e1442870
    Closes-Bug: #1415943