svq1dec: call avcodec_set_dimensions() after dimensions changed.

Fixes NGS00148

Found-by: Phillip Langlois
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 4931c8f0f1)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 661ee45f88)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/svq1dec.c

@@ -676,6 +676,7 @@ static int svq1_decode_frame(AVCodecContext *avctx,
 #endif
     return result;
   }
+  avcodec_set_dimensions(avctx, s->width, s->height);
 
   //FIXME this avoids some confusion for "B frames" without 2 references
   //this should be removed after libavcodec can handle more flexible picture types & ordering