run_tests.sh: allow passing distro and baseurl
run_tests.sh: allow passing distro and baseurl

To enable DLRN fedora builds experimental jobs, it would be more
practical to be able to define those parameters.

Change-Id: I3e10f46a0ad92cb55a4c479c4ae6436741794699
Reference: https://review.rdoproject.org/r/#/c/10182

openstack-packages/delorean,openstack-packages/delorean,openstack-packages/DLRN,openstack-packages/DLRN