mingw: remove obsolete Group tag in RPM spec

Reviewed-by: NAndrea Bolognani <abologna@redhat.com>
Signed-off-by: NDaniel P. Berrangé <berrange@redhat.com>

mingw-libvirt.spec.in

@@ -39,7 +39,6 @@ Release:        1%{?dist}
 Summary:        MinGW Windows libvirt virtualization library
 
 License:        LGPLv2+
-Group:          Development/Libraries
 URL:            https://libvirt.org/
 
 %if %(echo %{version} | grep -q "\.0$"; echo $?) == 1