Added tracer for media scanning

Signed-off-by: Andrew DeMaria <lostonamountain@gmail.com>

libresonic-main/src/main/java/org/libresonic/player/service/MediaScannerService.java

@@ -220,6 +220,8 @@ public class MediaScannerService {
             LOG.info("Scanned media library with " + scanCount + " entries.");
         }
 
+        LOG.trace("Scanning file {}", file.getPath());
+
         searchService.index(file);
 
         // Update the root folder if it has changed.