Change instance variable to local variable in scenario/image/volume

There are still some unnecessary instance variables, and this is to
change them to local variables.

Change-Id: I9c9e25255e9d84639122156a618f266b91818743
diff --git a/tempest/api/image/v1/test_images.py b/tempest/api/image/v1/test_images.py
index a79c18c..756c78c 100644
--- a/tempest/api/image/v1/test_images.py
+++ b/tempest/api/image/v1/test_images.py
@@ -145,24 +145,24 @@
         a_formats = ['ami', 'ari', 'aki']
 
         (cls.container_format,
-         cls.container_format_alt) = CONF.image.container_formats[:2]
+         container_format_alt) = CONF.image.container_formats[:2]
         cls.disk_format, cls.disk_format_alt = CONF.image.disk_formats[:2]
         if cls.container_format in a_formats:
             cls.disk_format = cls.container_format
-        if cls.container_format_alt in a_formats:
-            cls.disk_format_alt = cls.container_format_alt
+        if container_format_alt in a_formats:
+            cls.disk_format_alt = container_format_alt
 
         img1 = cls._create_remote_image('one', cls.container_format,
                                         cls.disk_format)
-        img2 = cls._create_remote_image('two', cls.container_format_alt,
+        img2 = cls._create_remote_image('two', container_format_alt,
                                         cls.disk_format_alt)
         img3 = cls._create_remote_image('dup', cls.container_format,
                                         cls.disk_format)
         img4 = cls._create_remote_image('dup', cls.container_format,
                                         cls.disk_format)
-        img5 = cls._create_standard_image('1', cls.container_format_alt,
+        img5 = cls._create_standard_image('1', container_format_alt,
                                           cls.disk_format_alt, 42)
-        img6 = cls._create_standard_image('2', cls.container_format_alt,
+        img6 = cls._create_standard_image('2', container_format_alt,
                                           cls.disk_format_alt, 142)
         img7 = cls._create_standard_image('33', cls.container_format,
                                           cls.disk_format, 142)
diff --git a/tempest/api/volume/test_volumes_extend.py b/tempest/api/volume/test_volumes_extend.py
index 20118df..2e1851e 100644
--- a/tempest/api/volume/test_volumes_extend.py
+++ b/tempest/api/volume/test_volumes_extend.py
@@ -23,13 +23,13 @@
     @decorators.idempotent_id('9a36df71-a257-43a5-9555-dc7c88e66e0e')
     def test_volume_extend(self):
         # Extend Volume Test.
-        self.volume = self.create_volume()
-        extend_size = int(self.volume['size']) + 1
-        self.volumes_client.extend_volume(self.volume['id'],
+        volume = self.create_volume()
+        extend_size = int(volume['size']) + 1
+        self.volumes_client.extend_volume(volume['id'],
                                           new_size=extend_size)
         waiters.wait_for_volume_status(self.volumes_client,
-                                       self.volume['id'], 'available')
-        volume = self.volumes_client.show_volume(self.volume['id'])['volume']
+                                       volume['id'], 'available')
+        volume = self.volumes_client.show_volume(volume['id'])['volume']
         self.assertEqual(int(volume['size']), extend_size)
 
 
diff --git a/tempest/scenario/test_aggregates_basic_ops.py b/tempest/scenario/test_aggregates_basic_ops.py
index 50fe9c8..95c2d32 100644
--- a/tempest/scenario/test_aggregates_basic_ops.py
+++ b/tempest/scenario/test_aggregates_basic_ops.py
@@ -36,9 +36,8 @@
     def setup_clients(cls):
         super(TestAggregatesBasicOps, cls).setup_clients()
         # Use admin client by default
-        cls.manager = cls.admin_manager
-        cls.aggregates_client = cls.manager.aggregates_client
-        cls.hosts_client = cls.manager.hosts_client
+        cls.aggregates_client = cls.admin_manager.aggregates_client
+        cls.hosts_client = cls.admin_manager.hosts_client
 
     def _create_aggregate(self, **kwargs):
         aggregate = (self.aggregates_client.create_aggregate(**kwargs)
diff --git a/tempest/scenario/test_network_basic_ops.py b/tempest/scenario/test_network_basic_ops.py
index e6a5f51..4dae564 100644
--- a/tempest/scenario/test_network_basic_ops.py
+++ b/tempest/scenario/test_network_basic_ops.py
@@ -109,13 +109,13 @@
         self.check_networks()
 
         self.ports = []
-        self.port_id = None
+        port_id = None
         if boot_with_port:
             # create a port on the network and boot with that
-            self.port_id = self._create_port(self.network['id'])['id']
-            self.ports.append({'port': self.port_id})
+            port_id = self._create_port(self.network['id'])['id']
+            self.ports.append({'port': port_id})
 
-        server = self._create_server(self.network, self.port_id)
+        server = self._create_server(self.network, port_id)
         self._check_tenant_network_connectivity()
 
         floating_ip = self.create_floating_ip(server)