requirements should indicate module six required version #

[Tong Li]

Some modules in Ceilometer uses library six and uses method add_metaclass, however, that only existed in six 1.3.0 and above.
The ceilometer requirements.txt should be updated to reflect that.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/50492

[fujioka yuuichi (fujioka-yuuichi-d)]

Hi, Tong.

add_metaclass was released by 1.4.0.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/52066
Committed: http://github.com/openstack/keystone/commit/15670c65d8f0eed7469aba83c1e2435de233dffe
Submitter: Jenkins
Branch: master

commit 15670c65d8f0eed7469aba83c1e2435de233dffe
Author: Steven Hardy <email address hidden>
Date: Wed Oct 16 12:19:54 2013 +0100

    Add python-six to requirements

    missing python-six minimum version from the requirements.txt
    set the min version to 1.4.1, without six recent versions of
    keystone fail to start with a critical 'module' object has no
    attribute 'add_metaclass' error

    Change-Id: Ibfe2c9ec2457d3131dc9b6760e343c36ab8a3c38
    Closes-Bug: #1237089

[Alan Pevec (apevec)]

Fix merged to ceilometer (master) referencing duplicate bug 1237205
https://review.openstack.org/50538