Fix QNetworkReply test cases that use the MiniHttpServer on windows

Fix QNetworkReply test cases that use the MiniHttpServer on windows

The "happy eyeballs" connection code means that IPv4 and IPv6 connections
are both attempted for a http request.
For a normal http server, this is no problem, but the MiniHttpServer in
the test code is very simplistic and cannot cope with more than one
client connected at the same time.
On windows this causes all these tests to fail with timeouts.
Changed the MiniHttpServer to listen on IPv4 only instead of Any address.

Change-Id: I81e249997d894d266001da474a351b1f5642599e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>