[filescanner] Remove unnecessary query for file id in process_media

The previous query for db_file_stamp_bypath already retrieves the file
id for the given path.

src/filescanner.c

@@ -626,7 +626,7 @@ filescanner_process_media(char *path, time_t mtime, off_t size, int type, struct
     mfi = external_mfi;
 
   if (stamp)
-    mfi->id = db_file_id_bypath(path);
+    mfi->id = id;
 
   mfi->fname = strdup(filename);
   if (!mfi->fname)