run_tests: drop dupplicated code
run_tests: drop dupplicated code

install_modules script was run two times.
This patch fix it, so we run it one time.

Change-Id: I25e7a3e5a1267c7f30131502a87190698e21288b

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