lavfi/avfilter: raise filter_frame() error.

libavfilter/avfilter.c

@@ -329,8 +329,7 @@ int ff_request_frame(AVFilterLink *link)
     if (ret == AVERROR_EOF && link->partial_buf) {
         AVFrame *pbuf = link->partial_buf;
         link->partial_buf = NULL;
-        ff_filter_frame_framed(link, pbuf);
-        return 0;
+        ret = ff_filter_frame_framed(link, pbuf);
     }
     if (ret == AVERROR_EOF)
         link->closed = 1;