nilfs2: remove redundant super block commit

This removes redundant super block commit.

nilfs_write_super will call nilfs_commit_super to store super block
into block device.  However, nilfs_put_super will call
nilfs_commit_super right after calling nilfs_write_super.  So calling
nilfs_write_super in nilfs_put_super would be redundant.
Signed-off-by: NJiro SEKIBA <jir@unicus.jp>
Signed-off-by: NRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

fs/nilfs2/super.c

@@ -313,9 +313,6 @@ static void nilfs_put_super(struct super_block *sb)
 
 	lock_kernel();
 
-	if (sb->s_dirt)
-		nilfs_write_super(sb);
-
 	nilfs_detach_segment_constructor(sbi);
 
 	if (!(sb->s_flags & MS_RDONLY)) {