Don't set the hostname pattern in the config

This repeats what's already being set in the official Nerves systems.
When using this project on unofficial systems, it is a little weird to
override the hostnames.

Since examples are nice, this changes it to set the time on boot. This
gets the date a little closer to the real date and avoids all of the
1970 time logs on init.

Author: fhunleth

config/target.exs

@@ -10,7 +10,7 @@ config :shoehorn, init: [:nerves_runtime, :nerves_pack]
 # https://github.com/nerves-project/erlinit/ for more information on
 # configuring erlinit.
 
-config :nerves, :erlinit, hostname_pattern: "nerves-%s"
+config :nerves, :erlinit, update_clock: true
 
 # Use Ringlogger as the logger backend and remove :console.
 # See https://hexdocs.pm/ring_logger/readme.html for more information on