add explicit react version to remove warnings

Author: mcnamee

package.json

@@ -6,7 +6,7 @@
     "start": "node node_modules/react-native/local-cli/cli.js start"
   },
   "dependencies": {
-    "react": "^15.2.1",
+    "react": "15.2.1",
     "react-native": "^0.31.0",
     "react-native-db-models": "^0.1.3",
     "react-native-navbar": "^1.5.0",