PDS sources now have "repo" field, update database_build.py

Our database_build.py script assumes 2 or 3 fields with the following values: packageName, version, and description

Recently, the some of the files we retrieve from PDS (https://github.com/linux-on-ibm-z/PDS/) added a "repo" field, which breaks the logic in our script.

In order to keep production updated, I've manually edited the source json files, but we'll want this handled in the script.