ffv1dec: propagate return code from ffv1_common_init()

Fixes Ticket1824
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/ffv1dec.c

@@ -717,7 +717,8 @@ static av_cold int decode_init(AVCodecContext *avctx)
     FFV1Context *f = avctx->priv_data;
     int ret;
 
-    ffv1_common_init(avctx);
+    if ((ret = ffv1_common_init(avctx)) < 0)
+        return ret;
 
     if (avctx->extradata && (ret = read_extra_header(f)) < 0)
         return ret;