avcodec/h264: h264_set_erpic() clear destination

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

libavcodec/h264.c

@@ -3010,6 +3010,8 @@ static void h264_set_erpic(ERPicture *dst, H264Picture *src)
 {
     int i;
 
+    memset(dst, 0, sizeof(*dst));
+
     if (!src)
         return;