avformat/lrcdec: Fix memory leak in lrc_read_header()

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit ef5994e0)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/lrcdec.c

@@ -212,6 +212,7 @@ static int lrc_read_header(AVFormatContext *s)
     }
     ff_subtitles_queue_finalize(&lrc->q);
     ff_metadata_conv_ctx(s, NULL, ff_lrc_metadata_conv);
+    av_bprint_finalize(&line, NULL);
     return 0;
 }