tests: Fix old Ansible dependencies installed by Tox

tox.ini

@@ -56,10 +56,10 @@ basepython =
 deps =
     -r{toxinidir}/tests/requirements.txt
     mode_ansible: -r{toxinidir}/tests/ansible/requirements.txt
-    ansible2.3: ansible=2.3.3.0
+    ansible2.3: ansible==2.3.3.0
-    ansible2.4: ansible=2.4.6.0
+    ansible2.4: ansible==2.4.6.0
-    ansible2.8: ansible=2.8.3
+    ansible2.8: ansible==2.8.3
-    ansible2.9: ansible=2.9.6
+    ansible2.9: ansible==2.9.6
     ansible2.10: ansible-base<2.10.14
     ansible2.10: ansible==2.10.0
     ansible3: ansible-base<2.10.14