rcrun(8): Teach rcstart, rcstop and friends to handle other rc dirs.

rcrun(8): Teach rcstart, rcstop and friends to handle other rc dirs.

This commit makes rcrun(8) and its various incarnations work also with
rc scripts that are in either /usr/pkg/etc/rc.d or /usr/local/etc/rc.d
(the paths in rc.conf's local_startup, actually).

While here, do some cleanup:

* Remove some unneeded 'cd' commands (rcorder as we call it will already
  give the full path to the script)

* Remove extra whitespace at the end of the file

* Add a copyright.