test: Re-adding topo server setup.

I accidentally removed it here: https://github.com/youtube/vitess/pull/1020

Original commit was:

commit ddbbca247a
Author: Alain Jobart <alainjobart@google.com>
Date:   Thu Aug 20 12:20:56 2015 -0700

    Adding topo server setup to this test, required in some environments.

test/python_client_test.py

@@ -29,6 +29,8 @@ def setUpModule():
   global vtgateclienttest_port
   global vtgateclienttest_grpc_port
 
+  environment.topo_server().setup()
+
   vtgateclienttest_port = environment.reserve_ports(1)
   args = environment.binary_args('vtgateclienttest') + [
       '-log_dir', environment.vtlogroot,
@@ -49,6 +51,8 @@ def tearDownModule():
   utils.kill_sub_process(vtgateclienttest_process, soft=True)
   vtgateclienttest_process.wait()
 
+  environment.topo_server().teardown()
+
 
 class TestPythonClient(unittest.TestCase):
   CONNECT_TIMEOUT = 10.0