not a stream error. This also fixes an infinite loop on EOS during ASF file
playback, and Michael claims he "likes the patch" (ref: [PATCH] RTSP-MS
15/15: move packet_time_start zero value assignment in asf.c" mailinglist
tread).



git-svn-id: file:///var/local/repositories/ffmpeg/trunk@18552 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b