title: React-Native app is crashing on launch after adding react-native-admob module
body: <p>Below is my package.</p>
  
  <p><code>{
    "name": "wallpaper_rn",
    "version": "0.1.0",
    "private": true,
    "devDependencies": {
      "babel-preset-react-native-stage-0": "^1.0.1",
      "jest": "^23.6.0",
      "jest-react-native": "^18.0.0",
      "react-test-renderer": "16.3.1"
    },
    "scripts": {
      "start": "react-native start",
      "android": "react-native run-android",
      "ios": "react-native run-ios",
      "test": "jest"
    },
    "jest": {
      "preset": "react-native"
    },
    "dependencies": {
      "prop-types": "^15.6.2",
      "react": "16.4.1",
      "react-native": "~0.55.2",
      "react-native-admob": "^2.0.0-beta.5",
      "react-native-elements": "^0.19.1",
      "react-native-fetch-blob": "^0.10.8",
      "react-native-fs": "^2.11.17",
      "react-native-share": "^1.1.2",
      "react-native-splash-screen": "^3.1.1",
      "react-native-swiper": "^1.5.13",
      "react-native-vector-icons": "^5.0.0",
      "react-navigation": "^2.14.1",
      "react-redux": "^5.0.7",
      "recyclerlistview": "^1.3.4",
      "redux": "^4.0.0",
      "redux-thunk": "^2.3.0"
    }
  }
  </code></p>
  
  <p>I also tried react-native-admob (1.3.2) version.</p>
  
  <p>I just installed admob module and link it. After that app suddenly started crashing on launch even in debug mode.</p>