Can confirm that upgrade works fine after altering the pulp db.
For those not that familiar with the pulp and its db. The quick and dirty way would be similar to the following.
Settings can be found in:
/etc/pulp/settings.py
login with:
psql -h localhost -p 5432 -U pulp pulpcore
and update with:
update rpm_rpmrepository set package_signing_fingerprint='';
dont forget to do a backup prior.