title: Background color for UISearchController in UITableView
body: <p>I have a SearchController's search bar inserted programatically into a UITableView's tableHeaderView.  When I pull up to view the search bar or refresh the table, I get this weird darker gray that you can see in the following image, in between the refresher activity indicator and the search bar (this background color persists even when I remove the refresher view):</p>
  
  <p><img src="https://i.stack.imgur.com/aD3hp.png" alt="enter image description here"></p>
  
  <pre><code>tableView.tableHeaderView = searchController.searchBar
  </code></pre>
  
  <p>I've tried changing this background color in every way I can think of:</p>
  
  <pre><code>tableView.backgroundColor = UIColor.redColor()
  tableView.tableHeaderView!.backgroundColor = UIColor.redColor()
  searchController.searchBar.backgroundColor = UIColor.redColor()
  view.backgroundColor = UIColor.redColor()
  </code></pre>
  
  <p>Nothing works.  This dark gray isn't one of the custom colors I use in my project so I know I didn't set it manually.  As soon as I take out the searchController everything works just like before: that dark gray is replaced by the lighter gray seen everywhere else.</p>