Support non-interactive user password update

[OpenStack Infra]

https://review.openstack.org/265052
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commit 5cbecc130ef2aacd5d9bd265b814e6f8140374f9
Author: Guang Yee <email address hidden>
Date: Thu Jan 7 18:56:44 2016 -0800

    Support non-interactive user password update

    Currently user password update require interactive prompting of user's
    original password. This is problematic because we can't support
    non-interactive applications and therefore hinders automation. This
    patch make it possible by optionally accepting an
    '--original-password' argument. If specified, we would use it instead
    of prompting.

    DocImpact

    Change-Id: I2d994e8c2be949f7ae616ac1d1594fb94e1a27cd
    Closes-Bug: 1531360