Fix scrape job file names to ensure job_name is prefix

[treydock]

Pull Request (PR) description

This fixes a regression from 829aa4e. Basically I have dozens of profile classes that do things like this:

  @@prometheus::scrape_job { "${facts['networking']['fqdn']}-${name}":
    job_name => 'tcp-probe',
    targets  => $targets,
    labels   => {
      'host' => $facts['networking']['hostname'],
      'cluster' => lookup('prometheus_cluster'),
      'environment' => lookup('prometheus_environment'),
      'service' => $name,
      'module' => $module,
      'role'  => $role,
    }
  }

Before the referenced commit, this worked, now the filename lacks the job_name prefix and thus never picked up by prometheus. If the job_name is going to be hardcoded prefix in prometheus::config class then I think this module should always ensure scrape jobs have the job name as prefix.

[anarcat]

between this and #435, we now have the job name twice in the filename:

Notice: /Stage[main]/Prometheus::Config/Prometheus::Scrape_job[apache_perdulce.torproject.org_9117]/File[/etc/prometheus/file_sd_config.d/apache_apache_perdulce.torproject.org_9117.yaml]/ensure: defined content as '{md5}9e1a35d39f151eab884e55588321b5b2'

this used to be:

Notice: /Stage[main]/Prometheus::Config/File[/etc/prometheus/file_sd_config.d/apache_perdulce.torproject.org:9117.yaml]/ensure: removed

so i'll send a PR to fix this incongruity.