remove inaccurate docs

Summary:
Our docs suggest using this babel plugin to remove console.log statements in production. Unfortunately, it does not actually work when you run it on a new React Native project, and the root cause is that the plugin does not handle all cases correctly. See discussion in facebook#10412 . For now, we should just stop recommending that people use this plugin, because it doesn't work.
Closes facebook#12315

Differential Revision: D4538567

Pulled By: hramos

fbshipit-source-id: f3ae1b9143130a05601907ee902a02fc0b2818b0

docs/Performance.md

@@ -86,19 +86,6 @@ but their receipt is not necessary for the scroll to occur).
 
 When running a bundled app, these statements can cause a big bottleneck in the JavaScript thread. This includes calls from debugging libraries such as [redux-logger](https://github.com/evgenyrodionov/redux-logger), so make sure to remove them before bundling.
 
-> There is a [babel plugin](https://babeljs.io/docs/plugins/transform-remove-console/) that can remove all `console.*` calls. You need to install it first using `npm install babel-plugin-transform-remove-console --save`, and then edit (or create) `.babelrc` under your project directory like the following:
-```json
-{
-  "env": {
-    "production": {
-      "plugins": ["transform-remove-console"]
-    }
-  }
-}
-```
-Then it will automatically remove all `console.*` calls in a release (production) version of your project. However, the `console.*` calls will still be executed in the debug version of your project.
-
-
 #### Development mode (dev=true)
 
 JavaScript thread performance suffers greatly when running in dev mode.