btrfs: stop setting log_root_tree->log_root to NULL in btrfs_recover_log_trees()

There's no point in setting log_root_tree->log_root to NULL as this is
already NULL, we never assigned anything to it before and it's meaningless
as a log root never has a value other than NULL for the ->log_root field,
that can be not NULL only for non log roots.

Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: fdmanana

fs/btrfs/tree-log.c

@@ -7585,7 +7585,6 @@ int btrfs_recover_log_trees(struct btrfs_root *log_root_tree)
 	if (ret)
 		return ret;
 
-	log_root_tree->log_root = NULL;
 	clear_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags);
 	btrfs_put_root(log_root_tree);