Remove all usage of six library

Replace six with Python 3 style code.

Change-Id: I724eba28d1a88317655f9cb7da94716772cd01ab
diff --git a/manila_tempest_tests/common/remote_client.py b/manila_tempest_tests/common/remote_client.py
index 9970b0b..30e64c7 100644
--- a/manila_tempest_tests/common/remote_client.py
+++ b/manila_tempest_tests/common/remote_client.py
@@ -13,7 +13,6 @@
 import sys
 
 from oslo_log import log
-import six
 from tempest import config
 from tempest.lib.common import ssh
 from tempest.lib.common.utils import test_utils
@@ -47,7 +46,7 @@
                             msg = 'Could not get console_log for server %s'
                             LOG.debug(msg, self.server['id'])
                 # re-raise the original ssh timeout exception
-                six.reraise(*original_exception)
+                raise original_exception
             finally:
                 # Delete the traceback to avoid circular references
                 _, _, trace = original_exception
diff --git a/manila_tempest_tests/common/waiters.py b/manila_tempest_tests/common/waiters.py
index 5d8d344..056dab6 100644
--- a/manila_tempest_tests/common/waiters.py
+++ b/manila_tempest_tests/common/waiters.py
@@ -15,7 +15,6 @@
 
 import time
 
-import six
 from tempest import config
 from tempest.lib import exceptions
 
@@ -137,7 +136,7 @@
                            'dest': dest_host,
                            'share_id': share['id'],
                            'timeout': client.build_timeout,
-                           'status': six.text_type(statuses),
+                           'status': str(statuses),
                        })
             raise exceptions.TimeoutException(message)
     return share