Sync latest processutils from oslo-incubator

An earlier commit (Ia92aab76fa83d01c5fbf6f9d31df2463fc26ba5c) failed
to address ssh_execute(). This change set addresses ssh_execute.

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oslo-incubator head:

commit 4990535fb5f3e2dc9b397e1a18c1b5dda94ef1c4
Merge: 9f5c700 2a130bf
Author: Jenkins <jenkins@review.openstack.org>
Date:   Mon Sep 29 23:12:14 2014 +0000

    Merge "Script to list unreleased changes in all oslo projects"

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The sync pulls in the following changes (newest to oldest):

6a60f842 - Mask passwords in exceptions and error messages (SSH)

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Change-Id: Ie0caf32469126dd9feb44867adf27acb6e383958
Closes-Bug: #1377981