nilfs2: get rid of nilfs_segctor_req struct

This will clean up nilfs_segctor_req struct and the obscure request
argument passed among private methods of segment constructor.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/segment.h b/fs/nilfs2/segment.h
index 3d3ab2f..3155e0c 100644
--- a/fs/nilfs2/segment.h
+++ b/fs/nilfs2/segment.h
@@ -116,6 +116,7 @@
  * @sc_wait_daemon: Daemon wait queue
  * @sc_wait_task: Start/end wait queue to control segctord task
  * @sc_seq_request: Request counter
+ * @sc_seq_accept: Accepted request count
  * @sc_seq_done: Completion counter
  * @sc_sync: Request of explicit sync operation
  * @sc_interval: Timeout value of background construction
@@ -169,6 +170,7 @@
 	wait_queue_head_t	sc_wait_task;
 
 	__u32			sc_seq_request;
+	__u32			sc_seq_accepted;
 	__u32			sc_seq_done;
 
 	int			sc_sync;