[Dovecot] @2.0, --sysconfdir incorrectly populated with dovecot/*.conf

[PGNet Dev]

to document from #irc,

in 1.2.x, specifying

   ./configure ... --sysconfdir=/path/to/dir ...

correctly results in dovecot.conf looked for as "/path/to/dir/dovecot.conf".

in 2.0, dovecot incorrectly creates a dovecot dir in the sysconfdir,
and looks for,

  /path/to/dir/dovecot/dovecot.conf

2.0's behavior should be made consistent with the correct
implementation in 1.2.x, or clarified as different in --help/docs.

thanks.