Dropping the py35 testing

All the integration testing has been moved to
Bionic now[1] and py3.5 is not tested runtime for
Train or stable/stein[2].

As per below ML thread, we are good to drop the py35
testing now:
http://lists.openstack.org/pipermail/openstack-discuss/2019-April/005097.html

[1] http://lists.openstack.org/pipermail/openstack-discuss/2019-April/004647.html
[2]
https://governance.openstack.org/tc/reference/runtimes/stein.html
https://governance.openstack.org/tc/reference/runtimes/train.html

Change-Id: I1b98c34b0ab39123c4489bb638c96f726c2bdb88

.zuul.yaml

@@ -2,7 +2,6 @@
     templates:
       - check-requirements
       - openstack-python-jobs
-      - openstack-python35-jobs
       - openstack-python36-jobs
       - openstack-python37-jobs
     check:
@@ -16,9 +15,6 @@
         - openstack-tox-py27:
             required-projects:
               - openstack/nova
-        - openstack-tox-py35:
-            required-projects:
-              - openstack/nova
         - openstack-tox-py36:
             required-projects:
               - openstack/nova
@@ -36,9 +32,6 @@
         - openstack-tox-py27:
             required-projects:
               - openstack/nova
-        - openstack-tox-py35:
-            required-projects:
-              - openstack/nova
         - openstack-tox-py36:
             required-projects:
               - openstack/nova

setup.cfg

@@ -8,7 +8,7 @@ classifiers =
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.5
+    Programming Language :: Python :: 3.6
     Environment :: OpenStack
     Development Status :: 3 - Alpha
     Framework :: Setuptools Plugin

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py35,py34,py27,pep8
+envlist = py36,py27,pep8
 minversion = 2.0
 skipsdist = True