Log recording failure

If recording fails, log "recording failed" instead of "recording
complete".

app/src/recorder.c

@@ -216,13 +216,18 @@ recorder_close(struct recorder *recorder) {
     int ret = av_write_trailer(recorder->ctx);
     if (ret < 0) {
         LOGE("Failed to write trailer to %s", recorder->filename);
+        recorder->failed = true;
     }
     avio_close(recorder->ctx->pb);
     avformat_free_context(recorder->ctx);
 
+    if (recorder->failed) {
+        LOGE("Recording failed to %s", recorder->filename);
+    } else {
         const char *format_name = recorder_get_format_name(recorder->format);
         LOGI("Recording complete to %s file: %s", format_name, recorder->filename);
     }
+}
 
 static bool
 recorder_write_header(struct recorder *recorder, const AVPacket *packet) {