btrfs: Clean up dead code in root-tree

The value of variable 'can_recover' is never used after being set, thus
it should be removed, as it was never used since the first commit
68a7342c ("Btrfs: cleanup orphaned root orphan item").
Signed-off-by: Christos Gkekas <chris.gekas@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

fs/btrfs/root-tree.c

@@ -226,10 +226,6 @@ int btrfs_find_orphan_roots(struct btrfs_fs_info *fs_info)
 	struct btrfs_root *root;
 	int err = 0;
 	int ret;
-	bool can_recover = true;
-
-	if (sb_rdonly(fs_info->sb))
-		can_recover = false;
 
 	path = btrfs_alloc_path();
 	if (!path)