docs(graph): remove unused headers

docs/sources/reference/graph.md

@@ -48,12 +48,6 @@ populate the template variable to a desired value from the link.
 The metrics tab defines what series data and sources to render.  Each datasource provides different
 The metrics tab defines what series data and sources to render.  Each datasource provides different
 options.
 options.
 
 
-### Graphite
-
-### InfluxDB
-
-### OpenTSDB
-
 ## Axes & Grid
 ## Axes & Grid
 
 
 ![](/img/docs/v2/graph_axes_grid_options.png)
 ![](/img/docs/v2/graph_axes_grid_options.png)