Allow to override the  datasource name

Change-Id: Ieeeace081771b4840959cceb66b9dea248030482
diff --git a/grafana/client/init.sls b/grafana/client/init.sls
index 0638527..0573119 100644
--- a/grafana/client/init.sls
+++ b/grafana/client/init.sls
@@ -8,7 +8,7 @@
 
 grafana_client_datasource_{{ datasource_name }}:
   grafana3_datasource.present:
-  - name: {{ datasource_name }}
+  - name: {{ datasource.name|default(datasource_name) }}
   - type: {{ datasource.type }}
   - url: http://{{ datasource.host }}:{{ datasource.get('port', 80) }}
   {%- if datasource.access is defined %}