title: DownloadManager not adding the file extension
body: <p>I would like to download from my server *.apk file, the file type on the server is *.apk and the MIME is application/vnd.android.package-archive",
  when downloading with the DownloadManager the file is downloaded but it creating it without the extension "apk", I tried this</p>
  
  <pre><code>request.setMimeType("application/vnd.android.package-archive"); 
  </code></pre>
  
  <p>and still no luck the file created without the extension,
  when trying to download it with <strong>Chrome</strong> it worked perfectly... </p>
  
  <p>please help.</p>