dont write id3v2 header when writing .mp2 files

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@9924 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavformat/mp3.c

@@ -608,7 +608,7 @@ AVOutputFormat mp2_muxer = {
     0,
     CODEC_ID_MP2,
     0,
-    mp3_write_header,
+    NULL,
     mp3_write_packet,
     mp3_write_trailer,
 };