net-analyzer/nagios-core: move localstatedir to /var/lib/nagios.

net-analyzer/nagios-core: move localstatedir to /var/lib/nagios.

For whatever reason, the local state directory for nagios was
historically set to /var/nagios. The FHS (v3) states that local
application state should live under /var/lib instead, so this revision
sets it to /var/lib/nagios.

This could potentially be annoying to upgraders but is probably non-
fatal. The state directory holds logs and service status information
that can be regenerated if necessary. Doing so could lead to "extra"
service notifications, though. To mitigate this, a warning is emitted
telling upgraders how to migrate the state information if they choose
to do so.

Package-Manager: Portage-2.3.69, Repoman-2.3.16
Signed-off-by: Michael Orlitzky <mjo@gentoo.org>