Refactored "Prevented unneeded index creation on MySQL-InnoDB" (2ceb10f) to avoid setting db_index=False. Backport of 6bf7964023487f2a352084e74aca27aecb354d6c from master
Refactored "Prevented unneeded index creation on MySQL-InnoDB" (2ceb10f) to avoid setting db_index=False. Backport of 6bf7964023487f2a352084e74aca27aecb354d6c from master