[grafana] Update Dashboard for CPU Usage

[grafana] Update Dashboard for CPU Usage

After the introduction of the collectd_config roles, for generating
configs, some of the configs changed, as they were no longer relying on
collectd's defaults.
One of these was the cpu plugin, which configured ``ReportPercentage True``
by the config role. The effected the grafana dashboards, because the CPU
usage dashboard explicitly selected ``type=cpu``. With the values being
reported as percentage, collectd sets the ``type=percent`` for the metrics
stored in influx (which grafana retrieves), so the dashboards dodn't
have any data to display. By  removing the ``type=cpu`` filter, the CPU
metrics are once again showing in grafana, and will be shown whether the
CPU usage is reported in percentage or the default jiffies.

Signed-off-by: "Emma Foley <efoley@redhat.com>"
Change-Id: I03a6f01677514d888e7805358855947791ab173c