Update hosts page optionsComponents to be a getter

ui/src/hosts/containers/HostsPage.js

@@ -116,7 +116,7 @@ export class HostsPage extends Component {
       <div className="page hosts-list-page">
         <PageHeader
           titleText="Host List"
-          optionsComponents={this.optionsComponents()}
+          optionsComponents={this.optionsComponents}
           sourceIndicator={true}
         />
         <div className="page-contents">
@@ -137,7 +137,7 @@ export class HostsPage extends Component {
     )
   }
 
-  optionsComponents = () => {
+  get optionsComponents() {
     const {autoRefresh, onChooseAutoRefresh, onManualRefresh} = this.props
 
     return (