title: Error when downloading cygwin packages from mirror sites in installation phase
body: <p>I'm having these two problems when trying to install cygwin : </p>
  
  <ol>
  <li>When choosing "Direct Connection" or "Use Internet Explorer Settings" the installation wizard doesnt download any mirror site, even if those are accessible from my browser</li>
  <li>When I add manually a site and select it to proceed I get the error in the second and third pictures      </li>
  </ol>
  
  <p><a href="https://i.stack.imgur.com/9pTrA.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/9pTrA.jpg" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/bKsJ8.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/bKsJ8.jpg" alt=""></a>
  <a href="https://i.stack.imgur.com/GvoEw.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/GvoEw.jpg" alt="enter image description here"></a>  </p>
  
  <p>And here is the complete logs found under the cygwin install directory :  </p>
  
  <pre><code>2017/02/14 12:12:17 Starting cygwin install, version 2.877
  2017/02/14 12:12:17 User has backup/restore rights
  2017/02/14 12:12:17 io_stream_cygfile: fopen(/etc/setup/setup.rc) failed 2 No such file or directory
  2017/02/14 12:12:17 Current Directory: C:\Users\meee\Downloads
  2017/02/14 12:12:17 Could not open service McShield for query, start and stop. McAfee may not be installed, or we don't have access.
  2017/02/14 12:12:27 source: network install
  2017/02/14 12:12:29 root: C:\cygwin system
  2017/02/14 12:12:45 Selected local directory: C:\Users\meee\Downloads
  2017/02/14 12:12:50 net: IE5
  2017/02/14 12:14:21 site: http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/
  2017/02/14 12:14:23 mbox note: Internal Error:  gcrypt library error 60 illegal tag.
  2017/02/14 12:14:46 mbox note: Mirror Error:  Setup.ini signature http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/x86/setup.xz.sig from http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/ failed to verify.
  Possible corrupt mirror?  Setup.ini rejected.
  2017/02/14 12:14:48 mbox note: Internal Error:  gcrypt library error 60 illegal tag.
  2017/02/14 12:14:49 mbox note: Mirror Error:  Setup.ini signature http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/x86/setup.bz2.sig from http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/ failed to verify.
  Possible corrupt mirror?  Setup.ini rejected.
  2017/02/14 12:14:50 mbox note: Internal Error:  gcrypt library error 60 illegal tag.
  2017/02/14 12:14:51 mbox note: Mirror Error:  Setup.ini signature http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/x86/setup.ini.sig from http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/ failed to verify.
  Possible corrupt mirror?  Setup.ini rejected.
  2017/02/14 12:14:52 mbox note: Unable to get setup from &lt;http://mirrors.metapeer.com/cygwin/;mirrors.metapeer.com;United States;Washington/&gt;
  2017/02/14 12:14:53 io_stream_cygfile: fopen(/etc/setup/installed.db) failed 2 No such file or directory
  2017/02/14 12:15:04 io_stream_cygfile: fopen(/etc/setup/setup.rc) failed 2 No such file or directory
  2017/02/14 12:15:04 Ending cygwin install
  </code></pre>
  
  <p>How can I solve this error ?</p>