[HERCULES] Corrected a dangling pointer in various DBMap/DBIterator functions
- If the DBMap has the DB_RELEASE_DATA option set and it contains a
  pointer, the optional returned out_data will now have its pointer
  value set to NULL.
- Credits to Ind for discovering the issue.
https://github.com/HerculesWS/Hercules/commit/e474973e0a9f057fff212d4f6ba445d189993764