[py] Fix Docs generation.

A PR brought in dependencies but tox didn't like them so reverted them.

py/tox.ini

@@ -33,23 +33,7 @@ deps =
 [testenv:docs]
 skip_install = true
 deps =
-
-  docutils==0.11
-  Jinja2==2.7
-  MarkupSafe==0.18
-  Pygments==1.6
-  urllib3==1.23
-  certifi==2018.8.24
   Sphinx==1.8.2
-  py27: asn1crypto==0.24.0
-  py27: cffi==1.11.5
-  py27: cryptography==2.3.1
-  py27: enum34==1.1.6
-  py27: idna==2.7
-  py27: ipaddress==1.0.22
-  py27: pycparser==2.19
-  py27: pyOpenSSL==18.0.0
-  py27: six==1.11.0
 
 commands = sphinx-build -W -b html -d ../build/doctrees docs/source ../build/docs/api/py {posargs}