run_tests: run dstat before r10k'ing modules
run_tests: run dstat before r10k'ing modules

r10k install is randomling taking lot of time ot be installed [1].
This patch executes dstat before installing r10k & puppet modules, so we
can see in dstat logs what is consumming CPU & memory during r10k setup.

(1] http://goo.gl/XJ9xky)

Change-Id: Ie98bede043339b47e9e928e5c964a6ba70090860

openstack/puppet-openstack-integration,openstack/puppet-openstack-integration,openstack/puppet-openstack-integration