[SEBA-450] (part 2)

Add tox testing support on additional XOS library modules:

- xos-api
- xos-kafka (has no tests)
- xos-migrate (has no tests)
- xos-synchronizer

Change-Id: I98195bc9747971d3515882d517affe058dd86ac5
diff --git a/lib/xos-api/xosapi/convenience/service.py b/lib/xos-api/xosapi/convenience/service.py
index ab82908..8c9985a 100644
--- a/lib/xos-api/xosapi/convenience/service.py
+++ b/lib/xos-api/xosapi/convenience/service.py
@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from __future__ import absolute_import
+
 from xosapi.orm import ORMWrapper, register_convenience_wrapper