[SEBA-450] (part 1)

Refactoring, python3 compat, and tox tests on:

- xosconfig
- xosgenx
- xosutil

Eliminate use of yaml.load() which is unsafe, switch to yaml.safe_load()

More diagnostics during database migration

Change-Id: I0fae5782fca401603a7c4e4ec2b9269ad24bda97
diff --git a/lib/xos-genx/xos-genx-tests/test_field_graph.py b/lib/xos-genx/xos-genx-tests/test_field_graph.py
index cfb4c8b..c3c08a7 100644
--- a/lib/xos-genx/xos-genx-tests/test_field_graph.py
+++ b/lib/xos-genx/xos-genx-tests/test_field_graph.py
@@ -13,10 +13,11 @@
 # limitations under the License.
 
 
+from __future__ import absolute_import
 import unittest
 from xosgenx.jinja2_extensions import FieldNotFound
-from helpers import XProtoTestHelpers
 from xosgenx.generator import XOSProcessor, XOSProcessorArgs
+from helpers import XProtoTestHelpers
 from functools import reduce
 
 
@@ -75,7 +76,7 @@
             generate()
 
         self.assertEqual(
-            e.exception.message,
+            str(e.exception),
             'Field "B" not found in model "Foo", referenced from field "A" by option "unique_with"',
         )