h264: do not let invalid values in h->ref_count on ff_h264_decode_ref_pic_list_reordering() errors.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
(cherry picked from commit 2428b53f6d306d8d71dec34fa7b0af733d76cfac)

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
diff --git a/libavcodec/h264.c b/libavcodec/h264.c
index 3ea6133..c3771f2 100644
--- a/libavcodec/h264.c
+++ b/libavcodec/h264.c
@@ -3940,8 +3940,10 @@
         fill_default_ref_list(h);
     }
 
-    if(h->slice_type_nos!=FF_I_TYPE && decode_ref_pic_list_reordering(h) < 0)
+    if(h->slice_type_nos!=FF_I_TYPE && decode_ref_pic_list_reordering(h) < 0) {
+        h->ref_count[1]= h->ref_count[0]= 0;
         return -1;
+    }
 
     if(h->slice_type_nos!=FF_I_TYPE){
         s->last_picture_ptr= &h->ref_list[0][0];