Use virtualenv --system-site-packages
Use virtualenv --system-site-packages

Use packaged RPMs for python deps, so we can check all of them are
present.

This fixes https://github.com/rdo-infra/puppet-dlrn/issues/39

Change-Id: Iae34ca6284466adc28db12d7f0c5be9eee30f0f2

javierpena/puppet-delorean,javierpena/puppet-delorean,rdo-infra/puppet-dlrn,rdo-infra/puppet-dlrn,javierpena/puppet-delorean,rdo-infra/puppet-dlrn