Fix the scope to share a server between tests

In test_server_actions.py, one server is created in setUpClass()
and the server would be shared between all tests.
If the server status is not 'ACTIVE' before each test, rebuild_
server() deletes it and rebuilds a server again.

The server_id scope which is passed to rebuild_server() is class
variable not instance variable. In addition, the server_id scope
which is stored with the return value of rebuild_server() is
instance variable like the following:

  [[instance]]                         [[class]]
  self.server_id = self.rebuild_server(self.server_id)

If we need to rebuild a server, the server_id, which is passed to
rebuild_server(), cannot be changed due to its scope. As the result,
many server creations happens in each test.
Then it causes "Quota exceeded" exception.

This patch fixes the scope of server_id for sharing the same server
between each tests.

Change-Id: I72b4aa73a6c77cce3a8e777d4f78913fb0986f66
Closes-Bug: #1257641
diff --git a/tempest/api/compute/images/test_images_oneserver.py b/tempest/api/compute/images/test_images_oneserver.py
index 18e32d8..19a308a 100644
--- a/tempest/api/compute/images/test_images_oneserver.py
+++ b/tempest/api/compute/images/test_images_oneserver.py
@@ -49,7 +49,7 @@
             LOG.exception(exc)
             # Rebuild server if cannot reach the ACTIVE state
             # Usually it means the server had a serius accident
-            self.server_id = self.rebuild_server(self.server_id)
+            self.__class__.server_id = self.rebuild_server(self.server_id)
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/images/test_images_oneserver_negative.py b/tempest/api/compute/images/test_images_oneserver_negative.py
index 4cd41ee..6757e8a 100644
--- a/tempest/api/compute/images/test_images_oneserver_negative.py
+++ b/tempest/api/compute/images/test_images_oneserver_negative.py
@@ -50,7 +50,7 @@
             LOG.exception(exc)
             # Rebuild server if cannot reach the ACTIVE state
             # Usually it means the server had a serius accident
-            self.server_id = self.rebuild_server(self.server_id)
+            self.__class__.server_id = self.rebuild_server(self.server_id)
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index 5fa4c35..2e45b28 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -45,7 +45,7 @@
             self.client.wait_for_server_status(self.server_id, 'ACTIVE')
         except Exception:
             # Rebuild server if something happened to it during a test
-            self.server_id = self.rebuild_server(self.server_id)
+            self.__class__.server_id = self.rebuild_server(self.server_id)
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/servers/test_servers_negative.py b/tempest/api/compute/servers/test_servers_negative.py
index 7b86d2d..8142250 100644
--- a/tempest/api/compute/servers/test_servers_negative.py
+++ b/tempest/api/compute/servers/test_servers_negative.py
@@ -34,7 +34,7 @@
         try:
             self.client.wait_for_server_status(self.server_id, 'ACTIVE')
         except Exception:
-            self.server_id = self.rebuild_server(self.server_id)
+            self.__class__.server_id = self.rebuild_server(self.server_id)
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_server_actions.py b/tempest/api/compute/v3/servers/test_server_actions.py
index dc78a47..090f4dd 100644
--- a/tempest/api/compute/v3/servers/test_server_actions.py
+++ b/tempest/api/compute/v3/servers/test_server_actions.py
@@ -45,7 +45,7 @@
             self.client.wait_for_server_status(self.server_id, 'ACTIVE')
         except Exception:
             # Rebuild server if something happened to it during a test
-            self.server_id = self.rebuild_server(self.server_id)
+            self.__class__.server_id = self.rebuild_server(self.server_id)
 
     @classmethod
     def setUpClass(cls):
diff --git a/tempest/api/compute/v3/servers/test_servers_negative.py b/tempest/api/compute/v3/servers/test_servers_negative.py
index 7b86d2d..8142250 100644
--- a/tempest/api/compute/v3/servers/test_servers_negative.py
+++ b/tempest/api/compute/v3/servers/test_servers_negative.py
@@ -34,7 +34,7 @@
         try:
             self.client.wait_for_server_status(self.server_id, 'ACTIVE')
         except Exception:
-            self.server_id = self.rebuild_server(self.server_id)
+            self.__class__.server_id = self.rebuild_server(self.server_id)
 
     @classmethod
     def setUpClass(cls):