qga/service-win32.c: diagnostic output should go to stderr Acked-by: Michael Roth <mdroth@linux.vnet.ibm.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>