Replace the usage of 'manager' with 'os_primary'

In tempest, alias 'manager' has been moved to 'os_primary'
in version Pike, and it will be removed in version Queens.
This patch is to replace the usage of 'manager' with 'os_primary'.

For other details, please check:
https://review.openstack.org/#/c/457555/

Change-Id: I7c3740d8941b837767d576d4e9b1fb86cd164d59
diff --git a/manila_tempest_tests/tests/scenario/manager.py b/manila_tempest_tests/tests/scenario/manager.py
index 64c5e8a..d991d4b 100644
--- a/manila_tempest_tests/tests/scenario/manager.py
+++ b/manila_tempest_tests/tests/scenario/manager.py
@@ -48,45 +48,45 @@
     def setup_clients(cls):
         super(ScenarioTest, cls).setup_clients()
         # Clients (in alphabetical order)
-        cls.flavors_client = cls.manager.flavors_client
+        cls.flavors_client = cls.os_primary.flavors_client
         cls.compute_floating_ips_client = (
-            cls.manager.compute_floating_ips_client)
+            cls.os_primary.compute_floating_ips_client)
         if CONF.service_available.glance:
             # Check if glance v1 is available to determine which client to use.
             if CONF.image_feature_enabled.api_v1:
-                cls.image_client = cls.manager.image_client
+                cls.image_client = cls.os_primary.image_client
             elif CONF.image_feature_enabled.api_v2:
-                cls.image_client = cls.manager.image_client_v2
+                cls.image_client = cls.os_primary.image_client_v2
             else:
                 raise lib_exc.InvalidConfiguration(
                     'Either api_v1 or api_v2 must be True in '
                     '[image-feature-enabled].')
         # Compute image client
-        cls.compute_images_client = cls.manager.compute_images_client
-        cls.keypairs_client = cls.manager.keypairs_client
+        cls.compute_images_client = cls.os_primary.compute_images_client
+        cls.keypairs_client = cls.os_primary.keypairs_client
         # Nova security groups client
         cls.compute_security_groups_client = (
-            cls.manager.compute_security_groups_client)
+            cls.os_primary.compute_security_groups_client)
         cls.compute_security_group_rules_client = (
-            cls.manager.compute_security_group_rules_client)
-        cls.servers_client = cls.manager.servers_client
-        cls.interface_client = cls.manager.interfaces_client
+            cls.os_primary.compute_security_group_rules_client)
+        cls.servers_client = cls.os_primary.servers_client
+        cls.interface_client = cls.os_primary.interfaces_client
         # Neutron network client
-        cls.networks_client = cls.manager.networks_client
-        cls.ports_client = cls.manager.ports_client
-        cls.routers_client = cls.manager.routers_client
-        cls.subnets_client = cls.manager.subnets_client
-        cls.floating_ips_client = cls.manager.floating_ips_client
-        cls.security_groups_client = cls.manager.security_groups_client
+        cls.networks_client = cls.os_primary.networks_client
+        cls.ports_client = cls.os_primary.ports_client
+        cls.routers_client = cls.os_primary.routers_client
+        cls.subnets_client = cls.os_primary.subnets_client
+        cls.floating_ips_client = cls.os_primary.floating_ips_client
+        cls.security_groups_client = cls.os_primary.security_groups_client
         cls.security_group_rules_client = (
-            cls.manager.security_group_rules_client)
+            cls.os_primary.security_group_rules_client)
 
         if CONF.volume_feature_enabled.api_v2:
-            cls.volumes_client = cls.manager.volumes_v2_client
-            cls.snapshots_client = cls.manager.snapshots_v2_client
+            cls.volumes_client = cls.os_primary.volumes_v2_client
+            cls.snapshots_client = cls.os_primary.snapshots_v2_client
         else:
-            cls.volumes_client = cls.manager.volumes_client
-            cls.snapshots_client = cls.manager.snapshots_client
+            cls.volumes_client = cls.os_primary.volumes_client
+            cls.snapshots_client = cls.os_primary.snapshots_client
 
     # ## Test functions library
     #
@@ -139,7 +139,7 @@
 
         # Needed for the cross_tenant_traffic test:
         if clients is None:
-            clients = self.manager
+            clients = self.os_primary
 
         if name is None:
             name = data_utils.rand_name(self.__class__.__name__ + "-server")