btrfs: make btrfs_delete_delayed_insertion_item() return a boolean

btrfs: make btrfs_delete_delayed_insertion_item() return a boolean

There's no need to return an integer as all we need to do is return true
or false to tell whether we deleted a delayed item or not. Also the logic
is inverted since we return 1 (true) if we didn't delete and 0 (false) if
we did, which is somewhat counter intuitive. Change the return type to a
boolean and make it return true if we deleted and false otherwise.

Reviewed-by: Boris Burkov <boris@bur.io>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>