Override _setUp instead setUp when we use fixtures.Fixture

According to https://pypi.python.org/pypi/fixtures, prior to
version 1.3.0 fixtures recommended overriding setUp. This is
still supported, but since it is harder to write leak-free
fixtures in this fashion, it is not recommended. We should
override _setUp now.

Change-Id: Id269b706c44cdb9c12e075ccb69dcb6055b18a3c
Closes-Bug: 1476573

magnum/tests/conf_fixture.py

@@ -30,9 +30,7 @@ class ConfFixture(fixtures.Fixture):
     def __init__(self, conf):
         self.conf = conf
 
-    def setUp(self):
-        super(ConfFixture, self).setUp()
-
+    def _setUp(self):
         self.conf.set_default('host', 'fake-mini')
         self.conf.set_default('connection', "sqlite://", group='database')
         self.conf.set_default('sqlite_synchronous', False, group='database')

magnum/tests/policy_fixture.py

@@ -29,8 +29,7 @@ class PolicyFixture(fixtures.Fixture):
     def __init__(self, compat=None):
         self.compat = compat
 
-    def setUp(self):
-        super(PolicyFixture, self).setUp()
+    def _setUp(self):
         self.policy_dir = self.useFixture(fixtures.TempDir())
         self.policy_file_name = os.path.join(self.policy_dir.path,
                                              'policy.json')

magnum/tests/unit/db/base.py

@@ -71,9 +71,7 @@ class Database(fixtures.Fixture):
         models.Base.metadata.create_all(self.engine)
         db_migrate.stamp('head')
 
-    def setUp(self):
-        super(Database, self).setUp()
-
+    def _setUp(self):
         if self.sql_connection == "sqlite://":
             conn = self.engine.connect()
             conn.connection.executescript(self._DB)