Fix examples and missing code-block

This patch fixes a missing code-block section in the
capabilities section of service-api.rst, and fixes
the import of walk in the upload.py examples to support
both python2 and python3.

Change-Id: I572769f971f84e0029f2948e42c130e73517f434

doc/source/service-api.rst

@@ -756,6 +756,8 @@ the method docstring.
 For each successful call to list capabilities, a result dictionary will be
 returned with the contents described below:
 
+.. code-block:: python
+
     {
         'action': 'capabilities',
         'timestamp': <time of the call>,

examples/upload.py

@@ -1,6 +1,7 @@
 import logging
 
-from os.path import join, walk
+from os import walk
+from os.path import join
 from swiftclient.multithreading import OutputManager
 from swiftclient.service import SwiftError, SwiftService, SwiftUploadObject
 from sys import argv