admin/build-doc: use python3

to address sphinx-doc/sphinx#3620, we need to
use sphinx with its fix at
sphinx-doc/sphinx@e049f86
in other words, we need to use sphinx v2.0.0 and up. but sphinx 2.0
requires python >= 3.5, so we have to use python3 for building the
documents.

in this change:

* doc-requirements.txt: install python3 packages on debian derivatives
* build-doc: install python3.6 packages from EPEL7, and use python3
  venv for using sphinx2
* doc-requirements.txt: bump up all python packages to latest
  stable.

Signed-off-by: Kefu Chai <kchai@redhat.com>

admin/build-doc

@@ -20,7 +20,7 @@ if command -v dpkg >/dev/null; then
  exit 1
  fi
 elif command -v yum >/dev/null; then
- for package in python-devel python-pip python-virtualenv doxygen ditaa ant libxml2-devel libxslt-devel Cython graphviz; do
+ for package in python36-devel python36-pip python36-virtualenv doxygen ditaa ant libxml2-devel libxslt-devel python36-Cython graphviz; do
  if ! rpm -q --whatprovides $package >/dev/null ; then
  missing="${missing:+$missing }$package"
  fi
@@ -57,7 +57,7 @@ cd build-doc
 [ -z "$vdir" ] && vdir="$TOPDIR/build-doc/virtualenv"
 
 if [ ! -e $vdir ]; then
- virtualenv --system-site-packages $vdir
+ virtualenv --python=python3 --system-site-packages $vdir
 fi
 $vdir/bin/pip install --quiet -r $TOPDIR/admin/doc-requirements.txt
 

admin/doc-requirements.txt

@@ -1,7 +1,4 @@
-Sphinx == 1.8.3
+Sphinx == 2.1.2
 git+https://github.com/ceph/sphinx-ditaa.git@py3#egg=sphinx-ditaa
-# newer versions of breathe will require Sphinx >= 2.0.0 and are Python3 only
-breathe==4.12.0
-# 4.2 is not yet release at the time of writing, to address CVE-2017-18342,
-# we have to use its beta release.
-pyyaml>=4.2b1
+breathe == 4.13.1
+pyyaml >= 5.1.2

doc_deps.deb.txt

@@ -1,13 +1,13 @@
 git
 gcc
-python-dev
-python-pip
-python-virtualenv
+python3-dev
+python3-pip
+python3-virtualenv
 doxygen
 ditaa
 libxml2-dev
 libxslt1-dev
 graphviz
 ant
 zlib1g-dev
-cython
+cython3