radioactivity_votingapi, radioactivity_up_down_voting:

o Use correct votingapi callback, it is:
  <module;>_votingapi_insert(...)

Side note:
o radioactivity_votingapi used callback <module;>_insert(...). It
  worked because that actually matched module <code>radioactivity</code> which is a dependency
  for radioactivity_votingapi. However, using same pattern for
  <code>radioactivity_up_down_voting</code> obviously missed
  the votinga callback... Hope we got this right this time!