Update to trafficserver release 4.0.1

* The autoconf config.layout patch for Arch has been merged upstream as
  is no longer required.
* Output the upgrade instructions URL if we are upgrading from trafficserver
  3.x to 4.0 as some configuration changes might be required.
Ensure that trafficserver will start immediately after package install.

* The trafficserver daemons require the existence of /run/trafficserver
  temp directory to run.  If we remove the directory from the package
  something would have to create it before the server processes could
  successfully start.  If systemd is in use systemd-tmpfiles will still
  successfully create the directory on future reboots due to the
  configuration file.  As such leaving the /run/trafficserver directory
  in the package makes the most sense.
Output a log and cache cleanup message upon package removal.

* Removing the package does not remove the log files and the cache
  database.  Some people may want to keep the log files, but others
  may not.  Warn the package remover that these files still exist
  and must be removed manually if desired.