It seems uuidgen doesn't exist by default on the new trusty nodes [1].
There are quite a few projects that use uuidgen [2] so we need to
ensure it's on the node.

On Trusty, this is provided by the uuid-runtime package. Note that on
Centos & Fedora this is provided by util-linux which is already tehre.

[1] http://logs.openstack.org/75/292475/1/check/gate-telemetry-dsvm-integration-ceilometer/2e85d1f/logs/devstacklog.txt.gz#_2016-03-16_19_20_30_116
[2] http://codesearch.openstack.org/?q=uuidgen&i=nope&files=&repos=

Change-Id: I230836d8b644698473d0611931334c232cf00734