[compute] device_mapper needs to be in sync with libvirtd package

[Mark Vanderwiel]

With the update of libvirtd packages version 1.2.8-16, it implicitly requires higher version (1.02.93-3) of device-mapper on RHEL7.

We need to add the device_mapper to the libvirtd package list so they both get installed/upgraded together.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/163854

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/163854
Committed: https://git.openstack.org/cgit/stackforge/cookbook-openstack-compute/commit/?id=020f79404eaffa07aaab59972eedb324d91b010b
Submitter: Jenkins
Branch: master

commit 020f79404eaffa07aaab59972eedb324d91b010b
Author: Mark Vanderwiel <email address hidden>
Date: Thu Mar 12 09:42:13 2015 -0500

    Keep libvirt and device-mapper in sync on rhel

    These two packages are inter dependent for how nova uses them, but the
    packages are not linked with dependencies. So, with rhel 7, if the
    libvirt package get installed/updated, we should do the same with
    the device-mapper to try to keep them in sync.

    Change-Id: I0444a8ac4d42093f5b39787e867d9ac70c0e8263
    Closes-Bug: #1431387