[Flow] Fix or suppress errors in react-native for Flow v0.13.0

Libraries/AppRegistry/AppRegistry.js

@@ -68,7 +68,7 @@ var AppRegistry = {
     console.log(
       'Running application "' + appKey + '" with appParams: ' +
       JSON.stringify(appParameters) + '. ' +
-      '__DEV__ === ' + __DEV__ +
+      '__DEV__ === ' + String(__DEV__) +
       ', development-level warning are ' + (__DEV__ ? 'ON' : 'OFF') +
       ', performance optimizations are ' + (__DEV__ ? 'OFF' : 'ON')
     );