title: pm2 --update-env option seems not working
body: <p>I launched my node app by using ecosystem.config.js like this.</p>
  
  <p><code>pm2 start ecosystem.config.js</code></p>
  
  <p>And my ecosystem.config.js is here.</p>
  
  <pre><code>module.exports = {
    /**
    * Application configuration section
    * http://pm2.keymetrics.io/docs/usage/application-declaration/
    */
    apps : [
      // First application
      {
        name      : "API",
        script    : "./app/index.js",
        env: {
          COMMON_VARIABLE: "true"
        },
        env_production : {
          NODE_ENV: "production"
        }
      },
    ],
  
    /**
    * Deployment section
    * http://pm2.keymetrics.io/docs/usage/deployment/
    */
    deploy : {
      production : {
        user : "node",
        host : "212.83.163.1",
        ref  : "origin/master",
        repo : "git@github.com:repo.git",
        path : "/var/www/production",
        "post-deploy" : "npm install &amp;&amp; pm2 startOrRestart ecosystem.json --env production"
      },
      dev : {
        user : "node",
        host : "212.83.163.1",
        ref  : "origin/master",
        repo : "git@github.com:repo.git",
        path : "/var/www/development",
        "post-deploy" : "npm install &amp;&amp; pm2 startOrRestart ecosystem.json --env dev",
        env  : {
          NODE_ENV: "dev"
        }
      }
    }
  }
  </code></pre>
  
  <p>Then I tried to change the config file for watching mode on. I read <a href="http://pm2.keymetrics.io/docs/usage/application-declaration/#updating-configurations-of-already-running-applications" rel="noreferrer">this document</a> so, I added <code>watch: true</code> attribute, then I tried <code>pm2 restart ecosystem.config.js --update-env</code> for applying changed config.</p>
  
  <p>The app is restarted and attribute seems to be changed, because when I try <code>pm2 list</code> the watching is enabled. But my app is not restarted after change my code. </p>
  
  <p>So, I just tried <code>pm2 delete 0</code>, <code>pm2 start ecosystem.config.js</code> then It's working well.</p>
  
  <p>Why does <code>--update-env</code> options not working? What do I do wrong?</p>