Switch to newer openstackdocstheme version

Switch to openstackdocstheme 2.2.1 version. Using
this version will allow especially:
* Linking from HTML to PDF document
* Allow parallel building of documents
* Fix some rendering problems

Update Sphinx version as well.

Disable openstackdocs_auto_name to use 'project' variable as name.

Change pygments_style to 'native' since old theme version always used
'native' and the theme now respects the setting and using 'sphinx' can
lead to some strange rendering.

openstackdocstheme renames some variables, so follow the renames
before the next release removes them. A couple of variables are also
not needed anymore, remove them.

See also
http://lists.openstack.org/pipermail/openstack-discuss/2020-May/014971.html

Change-Id: If08d763c2c0f09faa61c327ab64f1ad7b1549262

doc/source/conf.py

@@ -40,9 +40,10 @@ extensions = [
              ]
 
 # config for openstackdocstheme
-repository_name = 'openstack/glance-specs'
-bug_project = 'glance'
-bug_tag = 'glance-specs'
+openstackdocs_repo_name = 'openstack/glance-specs'
+openstackdocs_auto_name = False
+openstackdocs_bug_project = 'glance'
+openstackdocs_bug_tag = 'glance-specs'
 
 # Feed configuration for yasfb
 feed_base_url = 'http://specs.openstack.org/openstack/glance-specs'
@@ -99,7 +100,7 @@ add_module_names = False
 show_authors = False
 
 # The name of the Pygments (syntax highlighting) style to use.
-pygments_style = 'sphinx'
+pygments_style = 'native'
 
 # A list of ignored prefixes for module index sorting.
 modindex_common_prefix = ['glance-specs.']

requirements.txt

@@ -1,10 +1,10 @@
 actdiag
 blockdiag
 nwdiag
-openstackdocstheme>=1.32.0 # Apache-2.0
+openstackdocstheme>=2.2.1 # Apache-2.0
 pbr>=2.0 # Apache-2.0
 seqdiag
-sphinx>=1.6.2 # BSD
+sphinx>=2.0.0,!=2.1.0 # BSD
 sphinxcontrib-actdiag
 sphinxcontrib-blockdiag
 sphinxcontrib-nwdiag