lavf/oggopus: Fixing a log message

Re-wording a log message that's no longer true and changing its
severity level to debug.

Signed-off by: Vignesh Venkatasubramanian <vigneshv@google.com>

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

libavformat/oggparseopus.c

@@ -119,8 +119,8 @@ static int opus_packet(AVFormatContext *avf, int idx)
         if (skip > 0) {
             os->pduration = skip < os->pduration ? os->pduration - skip : 1;
             os->end_trimming = skip;
-            av_log(avf, AV_LOG_WARNING,
-                   "Last packet must be truncated to %d (unimplemented).\n",
+            av_log(avf, AV_LOG_DEBUG,
+                   "Last packet was truncated to %d due to end trimming.\n",
                    os->pduration);
         }
     }