Fix decoding ATI VCR2 codec, sample in

samples/V-codecs/ATI-VCR12/ATI/VCR2test.avi
Software decoding was broken since r8865, when two new context variables
were added, but not initialized in vcr2_init_sequence().
Another such context variable was added in r18381.

Originally committed as revision 21438 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpeg12.c

@@ -2092,6 +2092,9 @@ static int vcr2_init_sequence(AVCodecContext *avctx)
     s->chroma_format = 1;
     s->codec_id= s->avctx->codec_id= CODEC_ID_MPEG2VIDEO;
     avctx->sub_id = 2; /* indicates MPEG-2 */
+    s1->save_width           = s->width;
+    s1->save_height          = s->height;
+    s1->save_progressive_seq = s->progressive_sequence;
     return 0;
 }