Increase Keypair name size to 255

[Lin Hua Cheng]

The keypair name in horizon has a max_length of 20 characters, it seems short.

We should just match the nova data model length, and set the max_length to 255 for consistency.

Link to nova code: https://github.com/openstack/nova/blob/master/nova/db/sqlalchemy/models.py#L721

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/59596

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/59596
Committed: http://github.com/openstack/horizon/commit/35161baa8456e0ee59b910364507f7fa5955d382
Submitter: Jenkins
Branch: master

commit 35161baa8456e0ee59b910364507f7fa5955d382
Author: Zhenguo Niu <email address hidden>
Date: Tue Dec 3 09:56:49 2013 +0800

    Increase Keypair name size to 255

    The keypair name in horizon has a max_length of 20 characters, it seems short.
    We should just match the nova data model length, and set the max_length to 255
    for consistency.

    Change-Id: I53e43a792da677c39127ab43831dde5f70e588d3
    Closes-Bug: #1257030