title: Downgrade to react 15.6.2 from react 16.2.0 failed
body: <p>I recently upgraded to react <code>16.2.0</code> from react <code>15.6.2</code>
  Now my application doesnt work as expected and has lot of warnings for dependancies on react <code>15.6.2</code>
  So for me now its not possible to upgrade all other dependencies to <code>16.2.0.</code> because of the time schedule.
  Hence I want to downgrade to react <code>15.6.2</code></p>
  
  <p>I ran following commands to install react 15.6.2 again:</p>
  
  <pre><code>npm install react@^15.6.2
  </code></pre>
  
  <p>I am getting following error :</p>
  
  <pre><code>+-- UNMET PEER DEPENDENCY react@15.6.2 invalid
  `-- UNMET PEER DEPENDENCY react-dom@16.2.0
  </code></pre>
  
  <p>When I update my package.json to <code>"react": "^15.6.2"</code>, I get following error:</p>
  
  <pre><code>npm ERR! Linux 3.13.0-36-generic
  npm ERR! argv "/home/rakesh/.nvm/versions/node/v6.9.4/bin/node" "/home/rakesh/.nvm/versions/node/v6.9.4/bin/npm" "install"
  npm ERR! node v6.9.4
  npm ERR! npm  v3.10.10
  npm ERR! code EBADPLATFORM
  
  npm ERR! notsup Unsupported platform for fsevents@1.1.3: wanted {"os":"darwin","arch":"any"} (current: {"os":"linux","arch":"x64"})
  npm ERR! notsup Valid OS:    darwin
  npm ERR! notsup Valid Arch:  any
  npm ERR! notsup Actual OS:   linux
  npm ERR! notsup Actual Arch: x64
  
  npm ERR! Please include the following file with any support request:
  npm ERR!     /home/rakesh/rockethire/development/codebase/recruitment/rh-react/npm-debug.log
  </code></pre>
  
  <p>Below is my <code>package.json</code></p>
  
  <pre><code>{
    "name": "rh-react",
    "version": "1.0.0",
    "description": "Pages accessible for outside world",
    "main": "index.js",
    "scripts": {
      "test": "echo \"Error: no test specified\" &amp;&amp; exit 1",
      "dev": "webpack -d --watch",
      "build": "sh -ac '. .env; webpack -d'",
      "build:test": "sh -ac '. .env.test; webpack -p'",
      "build:prod": "sh -ac '. .env.prod; webpack -p'"
    },
    "author": "",
    "license": "ISC",
    "dependencies": {
      "ag-grid": "^13.3.1",
      "ag-grid-react": "^13.3.0",
      "axios": "^0.17.1",
      "babel-loader": "^7.1.2",
      "babel-plugin-add-module-exports": "^0.2.1",
      "babel-preset-es2015": "^6.24.1",
      "babel-preset-react": "^6.24.1",
      "bootstrap": "^3.3.7",
      "classnames": "^2.2.5",
      "dotenv": "^4.0.0",
      "fsevents": "^1.1.3",
      "jquery": "^3.2.1",
      "moment": "^2.19.1",
      "query-string": "^5.0.0",
      "react": "^16.2.0",
      "react-async-script-loader": "^0.3.0",
      "react-click-outside": "^3.0.0",
      "react-cookies": "^0.1.0",
      "react-datepicker": "^0.61.0",
      "react-datetime": "^2.11.1",
      "react-dom": "^16.2.0",
      "react-dom-factories": "^1.0.2",
      "react-dropzone": "^4.2.3",
      "react-dropzone-component": "^3.0.0",
      "react-moment": "^0.6.5",
      "react-notifications": "^1.4.3",
      "react-nvd3": "^0.5.7",
      "react-router": "^2.8.1",
      "react-router-dom": "^4.2.2",
      "react-scripts": "^1.0.17",
      "react-select": "^1.0.0-rc.10",
      "react-select2-wrapper": "^1.0.4-beta5",
      "reactjs-localstorage": "0.0.5",
      "webpack": "^3.9.1",
      "whatwg-fetch": "^2.0.3"
    },
    "devDependencies": {
      "babel-core": "^6.26.0",
      "babel-loader": "^7.1.2",
      "babel-preset-env": "^1.6.0",
      "babel-preset-stage-0": "^6.24.1",
      "compression-webpack-plugin": "^1.0.1",
      "css-loader": "^0.28.7",
      "eslint": "^4.11.0",
      "eslint-plugin-react": "^7.5.1",
      "style-loader": "^0.19.0",
      "uglifyjs-webpack-plugin": "^1.1.2",
      "webpack": "^3.6.0",
      "webpack-bundle-analyzer": "^2.9.1"
    }
  }
  </code></pre>
  
  <p>Anyone has idea why I am unable to downgrade?</p>