Port identity provider dashboard to Python 3

* Fix usage of Mapping() of keystoneclient.v3.contrib.federation:
  pass a manager instance, not a manager class.
* Simplify DataTable.get_object_display().
* tox.ini: add identity_providers to Python 3.4.

Co-Authored-By: Timur Sufiev <tsufiev@mirantis.com>
Closes-Bug: 1543073
Partial-Implements: blueprint porting-python3
Change-Id: I066359734624023b3f3776e8dbd54237d298e455

horizon/tables/base.py

@@ -1685,9 +1685,7 @@ class DataTable(object):
         By default, this returns a ``name`` attribute from the given object,
         but this can be overridden to return other values.
         """
-        if hasattr(datum, 'name'):
-            return datum.name
-        return None
+        return getattr(datum, 'name', None)
 
     def has_prev_data(self):
         """Returns a boolean value indicating whether there is previous data

openstack_dashboard/test/test_data/keystone_data.py

@@ -422,6 +422,6 @@ def data(TEST):
         ]
     }
     idp_mapping = mappings.Mapping(
-        mappings.MappingManager,
+        mappings.MappingManager(None),
         idp_mapping_dict)
     TEST.idp_mappings.add(idp_mapping)

tox.ini

@@ -29,6 +29,7 @@ commands =
         openstack_dashboard.dashboards.admin.metering \
         openstack_dashboard.dashboards.admin.routers \
         openstack_dashboard.dashboards.admin.volumes.volumes.tests \
+        openstack_dashboard.dashboards.identity.identity_providers \
         openstack_dashboard.dashboards.identity.users \
         openstack_dashboard.dashboards.project.access_and_security.api_access.tests \
         openstack_dashboard.dashboards.project.images \