Add backoff retry interval when creating volumes

This is a forward-porting of two patches from the puppet-coe-service-patch
module.  It introduces a backoff retry interval for volume creation.
The original commit messages from puppet-coe-service-patch follow:

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commit a2ab9c834cfb3fe855fb90d271d60d05bce901b2
Author: Ryan Uber <ru@ryanuber.com>
Date:   Thu Feb 13 13:17:18 2014 -0800

    Initial commit of module from allen sources
---
---
commit 36ea0e73629897f5ed80f95b8322abf85eb71eec
Author: Scott Pham <scpham@cisco.com>
Date:   Sat Mar 29 11:03:40 2014 -0400

    Adding Sharmins nova compute + cinder creation hook with backoff retry
    interval

    Change-Id: I307800ec8bbe141cd3f2553bc279ec380dfb7048
---

Implements: rally-user-story US4145
Implements: rally-task TA3473
Not-in-upstream: true