downgrade react version to make travis-ci happy

Author: chandu0101

package.json

@@ -15,11 +15,9 @@
     "webpack": "^1.9.10"
   },
   "dependencies": {
-    "enzyme": "^2.7.0",
-    "history": "^4.4.0",
     "jsdom": "^9.9.1",
-    "react": "next",
-    "react-addons-test-utils": "next",
-    "react-dom": "next"
+    "react": "15.4.2",
+    "react-addons-test-utils": "15.4.2",
+    "react-dom": "15.4.2"
   }
 }