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/common/progressbar.py

@@ -20,8 +20,9 @@ import six
 
 class _ProgressBarBase(object):
     """
-    Base abstract class used by specific class wrapper to show a progress bar
-    when the wrapped object are consumed.
+
+    Base abstract class used by specific class wrapper to show
+    a progress bar when the wrapped object are consumed.
 
     :param wrapped: Object to wrap that hold data to be consumed.
     :param totalsize: The total size of the data in the wrapped object.
@@ -51,8 +52,9 @@ class _ProgressBarBase(object):
 
 class VerboseFileWrapper(_ProgressBarBase):
     """
-    A file wrapper that show and advance a progress bar whenever file's read
-    method is called.
+
+    A file wrapper that show and advance a progress bar
+    whenever file's read method is called.
     """
 
     def read(self, *args, **kwargs):
@@ -69,9 +71,9 @@ class VerboseFileWrapper(_ProgressBarBase):
 
 class VerboseIteratorWrapper(_ProgressBarBase):
     """
+
     An iterator wrapper that show and advance a progress bar whenever
     data is consumed from the iterator.
-
     :note: Use only with iterator that yield strings.
     """