updated postConversion to use new extensions-based check
updated postConversion to use new extensions-based check

phtagn/sickbeard_mp4_automator,Filechaser/sickbeard_mp4_automator,phtagn/sickbeard_mp4_automator,Collisionc/sickbeard_mp4_automator,Filechaser/sickbeard_mp4_automator,Collisionc/sickbeard_mp4_automator