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: Ie7bcc327fd588a1ff6b2556d49017df56bc55bf8

.zuul.yaml

@@ -40,8 +40,8 @@
       zuul_work_dir: src/opendev.org/openstack/python-openstackclient
 
 - job:
-    name: osc-tox-py35-tips
-    parent: openstack-tox-py35
+    name: osc-tox-py36-tips
+    parent: openstack-tox-py36
     description: |
       Run unit tests for OpenStackClient with master branch of important libs.
 
@@ -180,11 +180,11 @@
     check:
       jobs:
         - osc-tox-py27-tips
-        - osc-tox-py35-tips
+        - osc-tox-py36-tips
     gate:
       jobs:
         - osc-tox-py27-tips
-        - osc-tox-py35-tips
+        - osc-tox-py36-tips
 
 - project:
     templates:
@@ -193,7 +193,6 @@
       - openstack-cover-jobs
       - openstack-lower-constraints-jobs
       - openstack-python-jobs
-      - openstack-python35-jobs
       - openstack-python36-jobs
       - openstack-python37-jobs
       - publish-openstack-docs-pti

setup.cfg

@@ -16,7 +16,6 @@ classifier =
     Programming Language :: Python :: 2
     Programming Language :: Python :: 2.7
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.5
     Programming Language :: Python :: 3.6
 
 [files]

tox.ini

@@ -1,6 +1,6 @@
 [tox]
 minversion = 2.3
-envlist = py36,py35,py27,pep8
+envlist = py36,py27,pep8
 skipdist = True
 
 [testenv]