title: React Router Redirect drops param
body: <p>I am using the <code>next</code> version of React Router, and it seems to be dropping params. I expect the redirect below to retain the value of <code>channelId</code>, but the <code>to</code> route uses the literal string "<code>:channelId</code>" in the path instead. </p>
  
  <pre><code>&lt;Switch&gt;
    &lt;Route exact path="/" component={Landing} /&gt;
    &lt;Route path="/channels/:channelId/modes/:modeId" component={Window} /&gt;
    &lt;Redirect
      from="/channels/:channelId"
      to="/channels/:channelId/modes/window" /&gt;
  &lt;/Switch&gt;
  </code></pre>
  
  <p>This looks like a <a href="https://github.com/ReactTraining/react-router/issues/1034#issuecomment-113526156" rel="noreferrer">resolved issue</a>, but it's not working. Is there something else I need to pass to the <code>to</code> route? </p>