[Part2]: Remove the six

The six should be removed completed in https://review.opendev.org/#/c/725167/
but missing, this PS to finish it.

more info: https://github.com/benjaminp/six/blob/master/six.py#L697

Change-Id: I6b0434fd8cbd5532bc8da30031faf00b9b87fd15

zun/common/utils.py

@@ -755,3 +755,15 @@ def is_port_active(neutron_port):
                          neutron client's 'show_port'
     """
     return (neutron_port['status'] == n_const.PORT_STATUS_ACTIVE)
+
+
+def reraise(tp, value, tb=None):
+    try:
+        if value is None:
+            value = tp()
+        if value.__traceback__ is not tb:
+            raise value.with_traceback(tb)
+        raise value
+    finally:
+        value = None
+        tb = None

zun/container/docker/utils.py

@@ -11,7 +11,6 @@
 # under the License.
 
 import contextlib
-import six
 import sys
 import tarfile
 
@@ -23,6 +22,7 @@ from oslo_utils import encodeutils
 from zun.common import consts
 from zun.common import exception
 from zun.common.i18n import _
+from zun.common import utils
 import zun.conf
 
 
@@ -46,7 +46,7 @@ def docker_client():
         )
     except errors.APIError as e:
         desired_exc = exception.DockerError(error_msg=str(e))
-        six.reraise(type(desired_exc), desired_exc, sys.exc_info()[2])
+        utils.reraise(type(desired_exc), desired_exc, sys.exc_info()[2])
 
 
 class DockerHTTPClient(docker.APIClient):

zun/network/kuryr_network.py

@@ -11,7 +11,6 @@
 #    under the License.
 
 import math
-import six
 import sys
 import time
 
@@ -22,6 +21,7 @@ from oslo_utils import excutils
 from zun.common import consts
 from zun.common import exception
 from zun.common.i18n import _
+from zun.common import utils
 import zun.conf
 from zun.network import network
 from zun.network import neutron
@@ -317,7 +317,7 @@ class KuryrNetwork(network.Network):
                     raise exception.SecurityGroupCannotBeApplied(
                         str(e))
                 else:
-                    six.reraise(*exc_info)
+                    utils.reraise(*exc_info)
             except Exception:
                 with excutils.save_and_reraise_exception():
                     LOG.exception("Neutron Error:")
@@ -350,7 +350,7 @@ class KuryrNetwork(network.Network):
                     raise exception.SecurityGroupCannotBeRemoved(
                         str(e))
                 else:
-                    six.reraise(*exc_info)
+                    utils.reraise(*exc_info)
             except Exception:
                 with excutils.save_and_reraise_exception():
                     LOG.exception("Neutron Error:")