Sync Sphinx requirement

1. Sync sphinx dependency with global requirements. It caps python 2 since
sphinx 2.0 no longer supports Python 2.7.
2. Update the UPPER_CONSTRAINTS_FILE for tox[1]
3. Update some URLs to latest

[1]: http://lists.openstack.org/pipermail/openstack-discuss/2019-May/006478.html

Change-Id: Ibe8c402c2817c31748e6a4b8344024a276609260

CONTRIBUTING.rst

@@ -1,9 +1,9 @@
 If you would like to contribute to the development of OpenStack, you must follow the steps in this page:
 
-http://docs.openstack.org/infra/manual/developers.html
+https://docs.openstack.org/infra/manual/developers.html
 If you already have a good understanding of how the system works and your OpenStack accounts are set up, you can skip to the development workflow section of this documentation to learn how changes to OpenStack should be submitted for review via the Gerrit tool:
 
-http://docs.openstack.org/infra/manual/developers.html#development-workflow
+https://docs.openstack.org/infra/manual/developers.html#development-workflow
 Pull requests submitted through GitHub will be ignored.
 
 Bugs should be filed on Launchpad, not GitHub:

test-requirements.txt

@@ -6,5 +6,6 @@ bashate>=0.5.1 # Apache-2.0
 hacking!=0.13.0,<0.14,>=0.12.0 # Apache-2.0
 
 docutils>=0.11 # OSI-Approved Open Source, Public Domain
-sphinx!=1.6.6,!=1.6.7,>=1.6.2 # BSD
+sphinx!=1.6.6,!=1.6.7,>=1.6.2,<2.0.0;python_version=='2.7'  # BSD
+sphinx!=1.6.6,!=1.6.7,!=2.1.0,>=1.6.2;python_version>='3.4'  # BSD
 openstackdocstheme>=1.18.1 # Apache-2.0

tools/docker_builder.sh

@@ -51,7 +51,7 @@ if ! is_docker_installed; then
         "fedora" | "rhel" | "centos")
             if [ ${platform} = "centos" ]; then
                 # install EPEL repo, in order to install argparse
-                sudo rpm -Uvh --force http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
+                sudo rpm -Uvh --force https://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
             fi
             sudo yum install docker -y
             ;;

tox.ini

@@ -5,7 +5,7 @@ skipsdist = True
 
 [testenv]
 usedevelop = True
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt} {opts} {packages}
+install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master} {opts} {packages}
 setenv =
     VIRTUAL_ENV={envdir}
 deps =