Remove k8s from dashboard title, make gauges use datasource variable.

Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>

node-mixin/dashboards/use.libsonnet

@@ -84,8 +84,8 @@ local g = import 'grafana-builder/grafana.libsonnet';
         ),
       ),
 
-    'k8s-node-rsrc-use.json':
-      g.dashboard('K8s / USE Method / Node')
+    'node-rsrc-use.json':
+      g.dashboard('USE Method / Node')
       .addTemplate('instance', 'up{%(nodeExporterSelector)s}' % $._config, 'instance')
       .addRow(
         g.row('CPU')

node-mixin/lib/promgrafonnet/gauge.libsonnet

@@ -6,7 +6,7 @@ local prometheus = grafana.prometheus;
   new(title, query)::
     singlestat.new(
       title,
-      datasource='prometheus',
+      datasource='$datasource',
       span=3,
       format='percentunit',
       valueName='current',