Don't use SO_REUSEADDR on Win32 platforms

Don't use SO_REUSEADDR on Win32 platforms

SO_REUSEADDR on Windows is actually akin to SO_REUSEPORT
on Linux/BSD. ie it allows 2 apps to listen to the same
port at once. Thus we must not set it on Win32 platforms

See http://msdn.microsoft.com/en-us/library/windows/desktop/ms740621.aspx

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>