Missing DB permissions in fix_translations_credits script

During QA of bug #459132, the script ran for a while before erroring out with:

Traceback (most recent call last):
...
  File "/srv/staging.launchpad.net/staging/launchpad/lib/lp/translations/model/potmsgset.py", line 1062, in setTranslationCreditsToTranslated
    lock_timestamp=datetime.datetime.now(pytz.UTC))
  File "/srv/staging.launchpad.net/staging/launchpad/lib/lp/translations/model/potmsgset.py", line 856, in updateTranslation
    force_shared=force_shared, force_diverged=force_diverged)
...
  File "/srv/staging.launchpad.net/staging/launchpad/lib/lp/registry/model/person.py", line 1073, in assignKarma
    if (not self.is_valid_person
...
psycopg2.ProgrammingError: permission denied for relation validpersoncache

Apparently, we are also missing karma SELECT, INSERT, karmaaction SELECT permissions, and potranslation INSERT (for the new automated translation message) permissions, apart from already identified SELECT on teamparticipation and SELECT on validpersoncache.