Fix audio sync problem for AAC (or any other mpeg PS or TS audio decoded by decavcode...

Fix audio sync problem for AAC (or any other mpeg PS or TS audio decoded by decavcodec) with a sample rate other than 48KHz. This problem had already been fixed for decavcodecai (the 'internal' ffmpeg audio decoder that handles all input files but mpeg streams) so decavcodec was just changed to use the same logic.

git-svn-id: svn://localhost/HandBrake/trunk@2985 b64f7644-9d1e-0410-96f1-a4d463321fa5