Follow the new PTI for document build

- Follow new PTI for docs build
- Add sphinxcontrib.apidoc to replace pbr autodoc

REF:
https://governance.openstack.org/tc/reference/project-testing-interface.html
http://lists.openstack.org/pipermail/openstack-dev/2017-December/125710.html
http://lists.openstack.org/pipermail/openstack-dev/2018-March/128594.html

Co-Authored-By: Nguyen Hai <nguyentrihai93@gmail.com>
Change-Id: Id16a5eaa57bc0d96332849abfb62898e6766ef86

doc/source/conf.py

@@ -26,10 +26,18 @@ sys.path.insert(0, os.path.abspath(os.path.join(os.path.dirname(__file__),
 # Add any Sphinx extension module names here, as strings. They can be
 # extensions coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
 extensions = [
-    'sphinx.ext.autodoc',
     'openstackdocstheme',
+    'sphinxcontrib.apidoc',
 ]
 
+# sphinxcontrib.apidoc options
+apidoc_module_dir = '../../glanceclient'
+apidoc_output_dir = 'reference/api'
+apidoc_excluded_paths = [
+    'tests/*',
+    'tests']
+apidoc_separate_modules = True
+
 # openstackdocstheme options
 repository_name = 'openstack/python-glanceclient'
 bug_project = 'python-glanceclient'