title: child-process exec cwd, is not setting current working directory
body: <p>I am building a node.js application.
  For executing a command, I am using child-process.
  I have to need to change CWD(current working directory) before executing the command. so I have code like below.</p>
  
  <pre><code>const exec = require('child_process').exec;
  
    let opts = {
      "maxBuffer": 1024 * 5000,
      "timeout": toolTimeout,
      "cwd": /opt/somepath,
      "env": {
        "PATH": process.env.PATH + ':' + /opt/somepath,
        "LANG": "en_US.UTF-8"
      }
    };
    exec(command, opts, function(error, stdout, stderr) {
  }
  </code></pre>
  
  <p>but above setup is not working as its still not changing CWD before executing command and command is executing from current directory where node file resides.
  Please help, if someone has any idea.</p>