btrfs: Remove unused flush var in shrink_delalloc

Added by 08e007d2e577 ("Btrfs: improve the noflush reservation") and
made redundant by 17024ad0a0fd ("Btrfs: fix early ENOSPC due to
delalloc").

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/extent-tree.c

@@ -4829,7 +4829,6 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
 	long time_left;
 	unsigned long nr_pages;
 	int loops;
-	enum btrfs_reserve_flush_enum flush;
 
 	/* Calc the number of the pages we need flush for space reservation */
 	items = calc_reclaim_items_nr(fs_info, to_reclaim);
@@ -4870,10 +4869,6 @@ static void shrink_delalloc(struct btrfs_fs_info *fs_info, u64 to_reclaim,
 			   atomic_read(&fs_info->async_delalloc_pages) <=
 			   (int)max_reclaim);
 skip_async:
-		if (!trans)
-			flush = BTRFS_RESERVE_FLUSH_ALL;
-		else
-			flush = BTRFS_RESERVE_NO_FLUSH;
 		spin_lock(&space_info->lock);
 		if (list_empty(&space_info->tickets) &&
 		    list_empty(&space_info->priority_tickets)) {