scripts: replace share icon with sitemap (graph)

fix confusing graph icon

Fixes #2511

client/app/scripts/components/view-mode-selector.js

@@ -29,7 +29,7 @@ class ViewModeSelector extends React.Component {
         <div className="tour-step-anchor view-mode-selector-wrapper">
           <ViewModeButton
             label="Graph"
-            icons="fa fa-share-alt"
+            icons="fa fa-sitemap"
             viewMode={GRAPH_VIEW_MODE}
             onClick={this.props.setGraphView}
           />