Disable configuration option not supported by nose.

$OpenBSD: patch-setup_cfg,v 1.4 2018/11/09 19:46:04 danj Exp $
Index: setup.cfg
--- setup.cfg.orig
+++ setup.cfg
@@ -8,7 +8,7 @@ license_file = LICENSE
 [nosetests]
 with-sqla_testing = true
 exclude = ^examples
-first-package-wins = true
+#first-package-wins = true
 where = test
 
 [tool:pytest]
