net-misc/openntpd added

Forked to address multiple issues:

 - #493084, add SIGINFO support through SIGUSR1 on systems without SIGINFO
   Thank you Paul for the patch!

 - #493078, no need for a symlink.

 - Using the standard "/var/empty" chroot environment (like already used
   for net-misc/openssh). Also, if you really need "/etc/localtime", you
   should alrady have workflow to keep your default chroot environment up
   to date.

 - #493032 fixed.

 - #493082 fixed, again thank you Paul for the patch!

 - Runscript will now set the "--wait" parameter for start-stop-
   daemon. This is needed to notice start problems (if privsep-path
   isn't owned by UID 0 and GID 0, openntpd will terminate and you
   won't notice (until you check the service status or read logs).
   Now, the start script will tell you when the daemon will exit within
   the first 500ms (default) due to an startup error.

 - Runscript will now verify ntpd's configuration before (re)starting.

 - Updated ebuild name to indicate we are using openntpd portable from
   20080406 at patchlevel 6.

 - No need to use sed to change NTPD_USER. We can use
   "--with-privsep-user" for that.

 - Setting LOCALSTATEDIR to "/var/lib/openntpd" (used for "ntpd.drift"
   file).

 - Removing drift file when unmerging net-misc/openntpd, so that the
   package can be completly removed (we only do that when
   "REPLACED_BY_VERSION" is empty, e.g. the package will be really removed
   and not reinstalled/updated).

 - Gentoo Prefix support immproved.