[block-storage] Need to allow san_private_key only option

[Mark Vanderwiel]

For the Storwise driver:

The san_login and san_password are not required when the san_private_key is provided. Need to allow flexibility to just provide the key and not require the san_login ('admin') to have a password. The default right now is to always require the san_login password in the databag which in many use cases is not known because on the key is being used.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/138480

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/138480
Committed: https://git.openstack.org/cgit/stackforge/cookbook-openstack-block-storage/commit/?id=e6d89d06894eb97cd907208b35a8d5ff6e8cabf1
Submitter: Jenkins
Branch: master

commit e6d89d06894eb97cd907208b35a8d5ff6e8cabf1
Author: Mark Vanderwiel <email address hidden>
Date: Tue Dec 2 12:32:54 2014 -0600

    Allow storwize private key without san_login and san_password

    Using The san_private_key by itself is a common use case. The
    current code requires the san_login and password to be set.
    This patch allows the key to be used without the login and password.
    Also removed some clutter comments from the conf template.

    Change-Id: Iea84c8310eec39481c115587219cdac35c9b3589
    Closes-Bug: #1398469