fuse_lib_opendir(): fix missing pthread_mutex_destroy() in error path

libfuse-lite/fuse.c

@@ -1813,6 +1813,7 @@ static void fuse_lib_opendir(fuse_req_t req, fuse_ino_t ino,
         }
     } else {
         reply_err(req, err);
+        pthread_mutex_destroy(&dh->lock);
         free(dh);
     }
     free(path);