Revert "Ensure virtualenv/pip are installed on centos"
Revert "Ensure virtualenv/pip are installed on centos"

This seems to be failing in all role tests, needs investigation.

This reverts commit 0a118003020c29e36ea669882378ddba4b03fd87.

Change-Id: If84d45acd2e49b4f4fd65d86670b6ac2621c3a70

openstack/openstack-ansible-openstack_hosts,openstack/openstack-ansible-openstack_hosts