document the options available for non-interactive installation in Debian

[Miguel Angel Nieto]

There are several options can be used to run a installation of Percona Server in non-interactive mode, but they are not documented:

root@debian:~# debconf-get-selections |grep percona
percona-server-server-5.7 percona-server-server-5.7/re-root-pass password
percona-server-server-5.7 percona-server-server-5.7/root-pass password
percona-server-server-5.7 percona-server-server-5.7/root-pass-mismatch error
percona-server-server-5.7 percona-server-server-5.7/data-dir note
percona-server-server-5.7 percona-server-server-5.7/remove-data-dir boolean false

Would be good if we could documente them.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-3390