title: Url.Action with protocol is returning a link without domain
body: <p>I'm using Url.Action to generate an absolute URL to send in an email. The link is generated inside a controller.</p>
  
  <pre><code>ConfirmLink = Url.Action(
      "ConfirmEmail",
      "Account",
      new { userId = user.Id, code },
      HttpContext.Request.Scheme
  )
  </code></pre>
  
  <p>For some reason, in local, I have this result:</p>
  
  <pre><code>http://localhost:5102/account/confirm-email?userId=10&amp;code=CfDJ8JH5BJKUsPZDnCLwFc3HSEHfe9Fk00NHiJqk36VbvkDbbV39AI7HY5m9pXVItwYE9%2B9ElTcnBSZiDNQ%2FmO5lx1tSnuvDmhzdzGlCQCfPQVe%2B21Nw03uNuBWoO8HCVivqzfudti579bWiaLW6PuuQQimn449YymVjgV3R36HeQID26jTmAxizDTqOsF1%2FvQc5Zw%3D%3D
  </code></pre>
  
  <p>but I have this result, without the domain/https protocol, in staging/prod:</p>
  
  <pre><code>http:///account/confirm-email?userId=10&amp;code=CfDJ8JH5BJKUsPZDnCLwFc3HSEHfe9Fk00NHiJqk36VbvkDbbV39AI7HY5m9pXVItwYE9%2B9ElTcnBSZiDNQ%2FmO5lx1tSnuvDmhzdzGlCQCfPQVe%2B21Nw03uNuBWoO8HCVivqzfudti579bWiaLW6PuuQQimn449YymVjgV3R36HeQID26jTmAxizDTqOsF1%2FvQc5Zw%3D%3D
  </code></pre>
  
  <p>I'm using ASP .NET Core with <code>"Microsoft.AspNetCore.Mvc": "1.1.0"</code>.</p>
  
  <p>Application published to IIS.</p>