Use formatter in server.py for "server list" tests.

We should use the formatter in the original code to set the
expected data in each test case.

The same problem exists in other test cases, like "server create".
But data structure in TestServerCreate is different from TestServerList,
so will fix the problem in another patch.

Change-Id: I233f7a91cd4cc1e996941e26ea85490fa3290572

Author: tang-chen

openstackclient/tests/compute/v2/test_server.py

@@ -674,7 +674,7 @@ def setUp(self):
                 s.id,
                 s.name,
                 s.status,
-                u'public=10.20.30.40, 2001:db8::5',
+                server._format_servers_list_networks(s.networks),
             ))
 
     def test_server_list_no_option(self):