Fix versions.csv creation when a commit has no rpms
Fix versions.csv creation when a commit has no rpms

In some cases, the last commit rpms column will be empty in the
database, which breaks DLRN when creating versions.csv.

Change-Id: Ie76b1c0acd6fb83315a32c7d1c56dbb835b6bca2

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