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: I6be901f8e01e0ff1b1e2b8c5197b320b5f8026fb

ironicclient/common/http.py

@@ -15,7 +15,6 @@
 
 import copy
 from distutils.version import StrictVersion
-import functools
 import hashlib
 import logging
 import os
@@ -234,7 +233,7 @@ _RETRY_EXCEPTIONS = (exc.Conflict, exc.ServiceUnavailable,
 
 def with_retries(func):
     """Wrapper for _http_request adding support for retries."""
-    @functools.wraps(func)
+    @six.wraps(func)
     def wrapper(self, url, method, **kwargs):
         if self.conflict_max_retries is None:
             self.conflict_max_retries = DEFAULT_MAX_RETRIES

ironicclient/v1/create_resources.py

@@ -10,7 +10,6 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
-import functools
 import json
 
 import jsonschema
@@ -114,7 +113,7 @@ def create_single_handler(resource_type):
     """
 
     def outer_wrapper(create_method):
-        @functools.wraps(create_method)
+        @six.wraps(create_method)
         def wrapper(client, **params):
             uuid = None
             error = None