Remove six

Python 2 is no longer supported, thus usage of six can be removed.

Change-Id: I1a44b65768cb862e10d013801dd47cb0510b2d07
diff --git a/heat_tempest_plugin/common/test.py b/heat_tempest_plugin/common/test.py
index 83ccdc2..3858859 100644
--- a/heat_tempest_plugin/common/test.py
+++ b/heat_tempest_plugin/common/test.py
@@ -21,10 +21,9 @@
 from neutronclient.common import exceptions as network_exceptions
 from oslo_log import log as logging
 from oslo_utils import timeutils
-import six
-from six.moves import urllib
 import testscenarios
 import testtools
+import urllib
 
 from heat_tempest_plugin.common import exceptions
 from heat_tempest_plugin.common import remote_client
@@ -67,7 +66,7 @@
 
 
 def rand_name(name=''):
-    randbits = six.text_type(random.randint(1, 0x7fffffff))
+    randbits = str(random.randint(1, 0x7fffffff))
     if name:
         return name + '-' + randbits
     else:
@@ -201,7 +200,7 @@
         self.setup_clients(self.conf, True)
 
     def get_remote_client(self, server_or_ip, username, private_key=None):
-        if isinstance(server_or_ip, six.string_types):
+        if isinstance(server_or_ip, str):
             ip = server_or_ip
         else:
             network_name_for_ssh = self.conf.network_for_ssh