Fix linux test

Signed-off-by: Jiahao XU <Jiahao_XU@outlook.com>

src/unix.rs

@@ -623,7 +623,7 @@ mod test {
         #[cfg(target_os = "linux")]
         {
             let client = new_client_from_pipe().0;
-            client.acquire().unwrap();
+            client.acquire().unwrap().drop_without_releasing();
             run_named_fifo_try_acquire_tests(&client);
         }
     }