- Copy stable/10 (r259064) to releng/10.0 as part of the
10.0-RELEASE cycle.
- Update __FreeBSD_version [1]
- Set branch name to -RC1

[1] 10.0-CURRENT __FreeBSD_version value ended at '55', so
start releng/10.0 at '100' so the branch is started with
a value ending in zero.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Update mail queue related periodic scripts to account for sendmail 8.12's
clientmqueue (submit mail queue).

The new mailq display is only active if both the old
daily_status_mailq_enable is set to "YES" and the new
daily_status_include_submit_mailq is set to "YES" so people who disabled
440.status-mailq won't have any surprises.

Likewise, the new queue run is only active if both the old
daily_queuerun_enable is set to "YES" and the new daily_submit_queuerun
is set to "YES" so people who disabled 500.queuerun won't have any
surprises.

While I am here, remove the [ ! -d /var/spool/mqueue ] checks from
both scripts as the queue directory isn't always /var/spool/mqueue for
the main daemon -- it can be set to anything in the sendmail.cf file.

MFC after: 1 week

Move the sendmail -q from cron to periodic, as suggested by a few people.
This has the benefit of adding a random start time element as daily
processing takes a different amount of time on different machines.