databases/percona57-*: update Percona MySQL to 5.7.41-44 release (+)

While here, introduce HAVE_TYPE_MY_BOOL variable alongside with typedef char my_bool;

This unbreak devel/apr1 build with mysql integration enabled whule dafault is set to percona

Release notes: https://docs.percona.com/percona-server/5.7/release-notes/5.7.41-44.html