Fix example error

Author: arniu

example/android/app/src/main/java/com/pushdemo/MainActivity.java

@@ -48,7 +48,7 @@ protected void onCreate(Bundle savedInstanceState) {
 
     @Override
     protected String getMainComponentName() {
-        return "PushDemoApp";
+        return "example";
     }
 
     @Override

example/android/settings.gradle

@@ -1,4 +1,4 @@
-rootProject.name = 'PushDemo'
+rootProject.name = 'example'
 include ':app', ':jpush-react-native', ':jcore-react-native'
 project(':jpush-react-native').projectDir = new File(rootProject.projectDir, '../node_modules/jpush-react-native/android')
 project(':jcore-react-native').projectDir = new File(rootProject.projectDir, '../node_modules/jcore-react-native/android')

example/index.js

@@ -12,4 +12,4 @@ const PushDemoApp = StackNavigator({
   }
 })
 
-AppRegistry.registerComponent('PushDemoApp', () => PushDemoApp)
+AppRegistry.registerComponent('example', () => PushDemoApp)