Enable flake8 checks

This commit enables new flake8 checks:
* E265  block comment should start with '# '
* H405  multi line docstring summary not separated with an empty line
* E123  closing bracket does not match indentation of opening bracket's line
* H238  old style class declaration, use new style (inherit from `object`)
* E128  continuation line under-indented for visual indent
and makes related changes in the code.

Change-Id: Ie993afc930f6b74d7a990bcaa9fc0e9f5ba1585c

glanceclient/tests/functional/base.py

@@ -17,10 +17,9 @@ from tempest_lib.cli import base
 
 
 class ClientTestBase(base.ClientTestBase):
-    """
-    This is a first pass at a simple read only python-glanceclient test. This
-    only exercises client commands that are read only.
+    """This is a first pass at a simple read only python-glanceclient test.
 
+    This only exercises client commands that are read only.
     This should test commands:
     * as a regular user
     * as an admin user