ccextractor: copy input buffer flags to output buffer

GST_VIDEO_BUFFER_FLAG_INTERLACED and GST_VIDEO_BUFFER_FLAG_TFF
flags are needed when processing SCTE 20 closed captions for an interlaced
stream, when we need to convert back to analog, in which case we need to match
the caption to the top or bottom field

ext/closedcaption/gstccextractor.c

@@ -377,6 +377,7 @@ gst_cc_extractor_handle_meta (GstCCExtractor * filter, GstBuffer * buf,
   if (tc_meta)
     gst_buffer_add_video_time_code_meta (outbuf, &tc_meta->tc);
 
+  gst_buffer_set_flags (outbuf, gst_buffer_get_flags (buf));
   /* We don't really care about the flow return */
   flow = gst_pad_push (filter->captionpad, outbuf);