Zero number of current scan after decoding one picture.

This fixes grayscale JPEG-LS decoding.

Originally committed as revision 6306 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mjpeg.c

@@ -2039,6 +2039,7 @@ static int mjpeg_decode_frame(AVCodecContext *avctx,
                         return -1;
                     break;
                 case EOI:
+                    s->cur_scan = 0;
                     if ((s->buggy_avid && !s->interlaced) || s->restart_interval)
                         break;
 eoi_parser: