Switch from global-redis-check for the example job's service name to
redis-cache. The former name is really confusing and someone finally
called us out on it:

https://groups.google.com/d/msg/nomad-tool/3RTh6CyYkWk/vEe_Sj7lAAAJ

Also specifically mention that the `service.name` parameter is what is
advertised in Consul.