create legacy.js to export es5 rules

packages/eslint-config-airbnb/base.js

@@ -1,23 +1,7 @@
 module.exports = {
   'extends': [
-    './rules/best-practices.js',
-    './rules/errors.js',
+    './legacy.js',
     './rules/es6.js',
-    './rules/legacy.js',
-    './rules/node.js',
-    './rules/strict.js',
-    './rules/style.js',
-    './rules/variables.js'
   ],
   'parser': 'babel-eslint',
-  'env': {
-    'browser': true,
-    'node': true,
-    'amd': false,
-    'mocha': false,
-    'jasmine': false
-  },
-  'ecmaFeatures': {},
-  'globals': {},
-  'rules': {}
 };

packages/eslint-config-airbnb/index.js

@@ -1,7 +1,6 @@
 module.exports = {
   'extends': [
-    // Need to qualify these here for ESLint to resolve them properly.
-    'airbnb/base',
-    'airbnb/rules/react.js'
+    './base.js',
+    './rules/react.js',
   ]
 };

packages/eslint-config-airbnb/legacy.js

@@ -0,0 +1,21 @@
+module.exports = {
+  'extends': [
+    './rules/best-practices.js',
+    './rules/errors.js',
+    './rules/legacy.js',
+    './rules/node.js',
+    './rules/strict.js',
+    './rules/style.js',
+    './rules/variables.js'
+  ],
+  'env': {
+    'browser': true,
+    'node': true,
+    'amd': false,
+    'mocha': false,
+    'jasmine': false
+  },
+  'ecmaFeatures': {},
+  'globals': {},
+  'rules': {}
+};