feat(graph): add spacing above Series specific overrides

public/app/plugins/panel/graph/module.ts

@@ -2,7 +2,7 @@
 
 import './graph';
 import './legend';
-import './seriesOverridesCtrl';
+import './series_overrides_ctrl';
 
 import moment from 'moment';
 import kbn from 'app/core/utils/kbn';

public/app/plugins/panel/graph/styleEditor.html

-<div class="editor-row">
+<div class="editor-row gf-form-row">
   <div class="section">
     <h5>Chart Options</h5>
 		<editor-opt-bool text="Bars" model="ctrl.panel.bars" change="ctrl.render()"></editor-opt-bool>

public/test/specs/seriesOverridesCtrl-specs.js

 define([
   './helpers',
-  'app/plugins/panel/graph/seriesOverridesCtrl'
+  'app/plugins/panel/graph/series_overrides_ctrl'
 ], function(helpers) {
   'use strict';