Simplified shouldComponentUpdate function in Controller example

Summary:
## Motivation (required)

I've been digging through the react-vr source code and I've noticed a conditional in one of the examples that can be simplified, this PR ensures that

## Test Plan (required)
`npm test` runs without any errors
Closes #107

Differential Revision: D4930440

Pulled By: andrewimm

fbshipit-source-id: 1115e49

Examples/Controller/index.vr.js

@@ -15,10 +15,7 @@ class PressState extends React.Component {
     if (nextProps.pressed !== this.props.pressed) {
       return true;
     }
-    if (nextState.hasFocus !== this.state.hasFocus) {
-      return true;
-    }
-    return false;
+    return nextState.hasFocus !== this.state.hasFocus;
   }
 
   render() {