btrfs: remove call to transaction commit trace in btrfs_cleanup_transaction()

btrfs: remove call to transaction commit trace in btrfs_cleanup_transaction()

We are not committing a transaction there, plus in subsequent patches we
want to change the argument for the trace event to be a transaction handle
instead of fs_info and in this context we don't have a transaction handle
(struct btrfs_trans_handle, only a struct btrfs_transaction). So remove the
call to the trace point.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>