Another uninitialized value.

See http://tranquillity.ath.cx/clang/2010-03-30-1/report-e6KUTb.html#EndPath

Originally committed as revision 22783 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavformat/rmdec.c

@@ -860,6 +860,7 @@ static int rm_read_packet(AVFormatContext *s, AVPacket *pkt)
                 len = !ast->audio_framesize ? RAW_PACKET_SIZE :
                     ast->coded_framesize * ast->sub_packet_h / 2;
                 flags = (seq++ == 1) ? 2 : 0;
+                pos = url_ftell(s->pb);
             } else {
                 len=sync(s, &timestamp, &flags, &i, &pos);
                 if (len > 0)