Code review comment for lp:~sergei.glushchenko/percona-xtrabackup/xb-tools

In addition to the above, I think api0internal.h has to be merged with
innodb_int.h, since the latter has the same purpose.

And api0log.c and api0print.c should have better name, I don't see a
point in following the InnoDB file naming conventions. Especially
because no one except Heikki knows the reason to name files like
xxx0yyy.c :)