Add 'description' option to os subnet create/set cmd

[Cao Xuan Hoang]

Current os subnet list and os subnet set commands missed 'description' option.

stack@stack:~/python-openstackclient$ openstack subnet create --help
WARNING: openstackclient.common.utils is deprecated and will be removed after Jun 2017. Please use osc_lib.utils
usage: openstack subnet create [-h] [-f {json,shell,table,value,yaml}]
                               [-c COLUMN] [--max-width <integer>]
                               [--noindent] [--prefix PREFIX]
                               [--project <project>]
                               [--project-domain <project-domain>]
                               [--subnet-pool <subnet-pool> | --use-default-subnet-pool]
                               [--prefix-length <prefix-length>]
                               [--subnet-range <subnet-range>]
                               [--dhcp | --no-dhcp] [--gateway <gateway>]
                               [--ip-version {4,6}]
                               [--ipv6-ra-mode {dhcpv6-stateful,dhcpv6-stateless,slaac}]
                               [--ipv6-address-mode {dhcpv6-stateful,dhcpv6-stateless,slaac}]
                               --network <network>
                               [--description <description>]
                               [--allocation-pool start=<ip-address>,end=<ip-address>]
                               [--dns-nameserver <dns-nameserver>]
                               [--host-route destination=<subnet>,gateway=<ip-address>]
                               name

stack@stack:~/python-openstackclient$ openstack subnet set --help
WARNING: openstackclient.common.utils is deprecated and will be removed after Jun 2017. Please use osc_lib.utils
usage: openstack subnet set [-h] [--name <name>] [--dhcp | --no-dhcp]
                            [--gateway <gateway>]
                            [--allocation-pool start=<ip-address>,end=<ip-address>]
                            [--dns-nameserver <dns-nameserver>]
                            [--host-route destination=<subnet>,gateway=<ip-address>]
                            <subnet>

It is expected to add [--description <description>] option to the commands for more flexibility.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/357060

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/357060
Committed: https://git.openstack.org/cgit/openstack/python-openstackclient/commit/?id=4265002e599af332f2e6288814dcaefa0dcb1be0
Submitter: Jenkins
Branch: master

commit 4265002e599af332f2e6288814dcaefa0dcb1be0
Author: Cao Xuan Hoang <email address hidden>
Date: Thu Aug 18 16:50:52 2016 +0700

    Add 'description' option to os subnet (pool) create/set cmd

    This patch adds '--description' option to the commands.

    Change-Id: Ifc2828670c3c48a87a0493d98686a5babf9b2ae7
    Closes-Bug: #1614458
    Closes-Bug: #1614823
    Partially-Implements: blueprint network-commands-options

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/python-openstackclient 3.3.0 release.