Fix H238 errors in tackerclient code

This Patch fixes all H238 errors and enables this test.

[H238]  Old style class declaration,
        use new style (inherit from `object`)

Change-Id: I184538cf6dcb97a178dcf017a21d878712063f91
Related-Bug: 1516045

tackerclient/tests/unit/test_cli10.py

@@ -46,7 +46,7 @@ def capture_std_streams():
         sys.stdout, sys.stderr = stdout, stderr
 
 
-class FakeStdout:
+class FakeStdout(object):
 
     def __init__(self):
         self.content = []

tackerclient/tests/unit/test_validators.py

@@ -19,7 +19,7 @@ from tackerclient.common import exceptions
 from tackerclient.common import validators
 
 
-class FakeParsedArgs():
+class FakeParsedArgs(object):
     pass
 
 

tox.ini

@@ -27,7 +27,6 @@ commands = python setup.py testr --coverage --testr-args='{posargs}'
 [flake8]
 # E125 continuation line does not distinguish itself from next logical line
 # H302 import only modules
-# H238 old style class declaration, use new style (inherit from `object`)
-ignore = E125,H302,H238
+ignore = E125,H302
 show-source = true
 exclude=.venv,.git,.tox,dist,doc,*openstack/common*,*lib/python*,*egg,tools