Don't use app node_modules folder as a resolve fallback (facebook#3884)

Author: gaearon

config/webpack.config.dev.js

@@ -95,7 +95,7 @@ module.exports = {
     // We placed these paths second because we want `node_modules` to "win"
     // if there are any conflicts. This matches Node resolution mechanism.
     // https://github.com/facebookincubator/create-react-app/issues/253
-    modules: ['node_modules', paths.appNodeModules].concat(
+    modules: ['node_modules'].concat(
       // It is guaranteed to exist because we tweak it in `env.js`
       process.env.NODE_PATH.split(path.delimiter).filter(Boolean)
     ),

config/webpack.config.prod.js

@@ -102,7 +102,7 @@ module.exports = {
     // We placed these paths second because we want `node_modules` to "win"
     // if there are any conflicts. This matches Node resolution mechanism.
     // https://github.com/facebookincubator/create-react-app/issues/253
-    modules: ['node_modules', paths.appNodeModules].concat(
+    modules: ['node_modules'].concat(
       // It is guaranteed to exist because we tweak it in `env.js`
       process.env.NODE_PATH.split(path.delimiter).filter(Boolean)
     ),