Enable Py36 Tests (#3972)

* add py36 to tox

* Add Python 3.6 tests to Travis

* Provide real path to python stdlib during tests

* set logs_dir in config_test

* set *_dirs in DetermineAccountTest

* Fix TLSSNI01Test

* Fix RenewalTest

* fix test_ancient_webroot_renewal_conf

tox.ini

@@ -4,7 +4,7 @@
 
 [tox]
 skipsdist = true
-envlist = modification,py{26,33,34,35},cover,lint
+envlist = modification,py{26,33,34,35,36},cover,lint
 
 # nosetest -v => more verbose output, allows to detect busy waiting
 # loops, especially on Travis
@@ -63,6 +63,13 @@ commands =
     pip install -e .[dev]
     nosetests -v certbot --processes=-1 --process-timeout=100
 
+[testenv:py36]
+commands =
+    pip install -e acme[dns,dev]
+    nosetests -v acme --processes=-1
+    pip install -e .[dev]
+    nosetests -v certbot --processes=-1 --process-timeout=100
+
 [testenv:py27_install]
 basepython = python2.7
 commands =