Remove flowtype/require-valid-file-annotation temporarily. (facebook#2311)

Until this issue (gajus/eslint-plugin-flowtype#165) is
fixed we're disabling `flowtype/require-valid-file-annotation`.

Author: Robdel12

packages/eslint-config-react-app/index.js

@@ -282,7 +282,8 @@ module.exports = {
 
     // https://github.com/gajus/eslint-plugin-flowtype
     'flowtype/define-flow-type': 'warn',
-    'flowtype/require-valid-file-annotation': 'warn',
+    // TODO: Reenable once https://github.com/gajus/eslint-plugin-flowtype/issues/165 is fixed
+    //'flowtype/require-valid-file-annotation': 'warn',
     'flowtype/use-flow-type': 'warn',
   },
 };