Remove unnecessary setUp() and tearDown() methods

It's unnecessary to implement setUp() and tearDown() when they only call
the parent class method of the same name.

Change-Id: I8a2c7f50e17def87ada8d4f1c1b554eb916afbd1

nova/tests/test_libvirt.py

@@ -171,9 +171,6 @@ class CacheConcurrencyTestCase(test.TestCase):
             'nova.virt.libvirt.imagebackend.libvirt_utils',
             fake_libvirt_utils))
 
-    def tearDown(self):
-        super(CacheConcurrencyTestCase, self).tearDown()
-
     def test_same_fname_concurrency(self):
         # Ensures that the same fname cache runs at a sequentially.
         uuid = uuidutils.generate_uuid()

nova/tests/test_virt_disk_vfs_localfs.py

@@ -148,10 +148,6 @@ class VirtDiskVFSLocalFSTestPaths(test.TestCase):
 
 
 class VirtDiskVFSLocalFSTest(test.TestCase):
-
-    def setUp(self):
-        super(VirtDiskVFSLocalFSTest, self).setUp()
-
     def test_makepath(self):
         global dirs, commands
         dirs = []

nova/tests/test_virt_drivers.py

@@ -192,9 +192,6 @@ class _VirtDriverTestCase(_FakeDriverBackendTestCase):
         self.ctxt = test_utils.get_test_admin_context()
         self.image_service = fake_image.FakeImageService()
 
-    def tearDown(self):
-        super(_VirtDriverTestCase, self).tearDown()
-
     def _get_running_instance(self):
         instance_ref = test_utils.get_test_instance()
         network_info = test_utils.get_test_network_info()