Update sphinx extension logging

Sphinx 1.6 deprecated using the application object to perform logging
and it will be removed in the upcoming 2.0 release. This updates our
extensions to use the recommended sphinx.util.logging instead.

Change-Id: I083f4debaa16d3bc2a3388bbb33c718b473563ef
Signed-off-by: Sean McGinnis <sean.mcginnis@gmail.com>

doc/source/_exts/workbooks.py

@@ -14,9 +14,12 @@ import os
 from docutils import nodes
 from docutils.parsers import rst
 from docutils.statemachine import ViewList
+from sphinx.util import logging
 from sphinx.util.nodes import nested_parse_with_titles
 import yaml
 
+LOG = logging.getLogger(__name__)
+
 
 WORKFLOW_PATH = os.path.abspath(
     os.path.join(os.path.dirname(__file__), '../../../workbooks', ))
@@ -87,7 +90,7 @@ def _write_workbook_pages(app):
 
     for name, workbook in all_workbooks.items():
         filename = 'doc/source/reference/workbooks/%s.rst' % name
-        app.info('generating workbook page for %s' % name)
+        LOG.info('generating workbook page for %s' % name)
         with open(filename, 'w') as f:
             f.write('\n'.join(_workbook_to_rst(name, workbook)))
         files.append(filename)
@@ -117,6 +120,6 @@ class WorkflowListDirective(rst.Directive):
 
 
 def setup(app):
-    app.info('loading workbooks extension')
+    LOG.info('loading workbooks extension')
     app.add_directive('workbooklist', WorkflowListDirective)
     _write_workbook_pages(app)