Replace use of functools.wraps() with six.wraps()

In Python 2.7, functools.wraps() does not provide the '__wrapped__'
attribute. This attribute is used by
oslo_utils.reflection.get_signature() when getting the signature of a
function. If a function is decorated without the '__wrapped__'
attribute then the signature will be of the decorator rather than the
underlying function.

From the six documentation for six.wraps():
    This is exactly the functools.wraps() decorator, but it sets the
    __wrapped__ attribute on what it decorates as functools.wraps()
    does on Python versions after 3.2.

Change-Id: I11bf2fa945d36bfbc89ec8239e7c9259e3e12496

ironic_inspector/main.py

@@ -11,12 +11,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import functools
 import os
 import re
 
 import flask
 from oslo_utils import uuidutils
+import six
 import werkzeug
 
 from ironic_inspector import api_tools
@@ -70,7 +70,7 @@ def error_response(exc, code=500):
 
 
 def convert_exceptions(func):
-    @functools.wraps(func)
+    @six.wraps(func)
     def wrapper(*args, **kwargs):
         try:
             return func(*args, **kwargs)
@@ -168,7 +168,7 @@ def api(path, is_public_api=False, rule=None, verb_to_rule_map=None,
     def outer(func):
         @app.route(path, **flask_kwargs)
         @convert_exceptions
-        @functools.wraps(func)
+        @six.wraps(func)
         def wrapper(*args, **kwargs):
             flask.request.context = context.RequestContext.from_environ(
                 flask.request.environ,

ironic_inspector/pxe_filter/base.py

@@ -14,7 +14,6 @@
 """Base code for PXE boot filtering."""
 
 import contextlib
-import functools
 
 from automaton import exceptions as automaton_errors
 from automaton import machines
@@ -23,6 +22,7 @@ from futurist import periodics
 from oslo_concurrency import lockutils
 from oslo_config import cfg
 from oslo_log import log
+import six
 import stevedore
 
 from ironic_inspector.common.i18n import _
@@ -74,7 +74,7 @@ State_space = [
 def locked_driver_event(event):
     """Call driver method having processed the fsm event."""
     def outer(method):
-        @functools.wraps(method)
+        @six.wraps(method)
         def inner(self, *args, **kwargs):
             with self.lock, self.fsm_reset_on_error() as fsm:
                 fsm.process_event(event)

ironic_inspector/test/unit/test_process.py

@@ -12,7 +12,6 @@
 # limitations under the License.
 
 import copy
-import functools
 import json
 import os
 import shutil
@@ -26,6 +25,7 @@ from oslo_config import cfg
 from oslo_serialization import base64
 from oslo_utils import timeutils
 from oslo_utils import uuidutils
+import six
 
 from ironic_inspector.common import ironic as ir_utils
 from ironic_inspector import db
@@ -524,7 +524,7 @@ class TestProcessNode(BaseTest):
 @mock.patch.object(node_cache, 'get_node', autospec=True)
 class TestReapply(BaseTest):
     def prepare_mocks(func):
-        @functools.wraps(func)
+        @six.wraps(func)
         def wrapper(self, pop_mock, *args, **kw):
             pop_mock.return_value = node_cache.NodeInfo(
                 uuid=self.node.uuid,
@@ -600,7 +600,7 @@ class TestReapplyNode(BaseTest):
         self.node_info.release_lock.assert_called_once_with(self.node_info)
 
     def prepare_mocks(fn):
-        @functools.wraps(fn)
+        @six.wraps(fn)
         def wrapper(self, release_mock, finished_mock, swift_mock,
                     *args, **kw):
             finished_mock.side_effect = lambda *a, **kw: \