Fix server id reference in _rebuild_server_and_check()

Reference to server id is broken now because
ServerActionsTestJSON(self) object has no attribute 'server'.

server attribute is passed as a method's argument.

Change-Id: I7ef97019a9db973749fa81875cfb9e5e837e6bea
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index a69dbb3..e1e7fda 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -190,7 +190,7 @@
                 server, self.os_primary, tenant_network,
                 True, self.validation_resources, "SSHABLE", True)
         else:
-            waiters.wait_for_server_status(self.client, self.server['id'],
+            waiters.wait_for_server_status(self.client, server['id'],
                                            'ACTIVE')
 
         msg = ('Server was not rebuilt to the original image. '