Copy stable/10@r272459 to releng/10.1 as part of
the 10.1-RELEASE process.

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

Prepare for the removal of set_rcvar() by changing the rcvar=
assignments to the literal values it would have returned.

The concept of set_rcvar() was nice in theory, but the forks
it creates are a drag on the startup process, which is especially
noticeable on slower systems, such as embedded ones.

During the discussion on freebsd-rc@ a preference was expressed for
using ${name}_enable instead of the literal values. However the
code portability concept doesn't really apply since there are so
many other places where the literal name has to be searched for
and replaced. Also, using the literal value is also a tiny bit
faster than dereferencing the variables, and every little bit helps.

Add the shutdown KEYWORD to those scripts that start persistent services
to allow them to do a "clean" shutdown.

I purposely avoided making changes to network-related stuff since the
system shutting down is pretty conclusive, and there may be complicated
dependencies on the network that I would rather not try to unravel.

I also skipped kerberos-related stuff for the reasons above, and
because I have no way to test it.

As previously discussed, add the svn:executable property to all scripts

When stopping powerd, set the CPU frequency back to its maximum value
(i.e., what it was almost certainly at before powerd was started).

Submitted by: R.B. Riddick
MFC after: 3 days

Use ${name} in pathnames where appropriate.
The sendmail script already was on this way,
but it didn't reach the end of it yet.

command_args is redundant.

Submitted by: Pawel Worach

Add an rc script for powerd(8).