common/_wait_for: ensure label_selectors is optional (#239) (#256)

[backport/2.2] common/_wait_for: ensure label_selectors is optional (#239)

Depends-On: ansible/ansible-zuul-jobs#1170
Depends-On: ansible/ansible-zuul-jobs#1169
Depends-On: ansible/ansible-zuul-jobs#1171
common/_wait_for: ensure label_selectors is optional
The label_selectors is a new parameter for _wait_for that was
introduced in #158.
The value is new and it can be set to None to make it optional. It should
not be mandatory a non optional parameter.
Reviewed-by: None 
Reviewed-by: Alina Buzachis 
Reviewed-by: None 
(cherry picked from commit 938f7e1)

Reviewed-by: None <None>
Reviewed-by: Gonéri Le Bouder <goneri@lebouder.net>
Reviewed-by: None <None>

changelogs/fragments/_wait_for_label_selector_optional.yaml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+- common - Ensure the label_selectors parameter of _wait_for method is optional.

plugins/module_utils/common.py

@@ -365,7 +365,7 @@ class K8sAnsibleMixin(object):
     def fail(self, msg=None):
         self.fail_json(msg=msg)
 
-    def _wait_for(self, resource, name, namespace, predicate, sleep, timeout, state, label_selectors):
+    def _wait_for(self, resource, name, namespace, predicate, sleep, timeout, state, label_selectors=None):
         start = datetime.now()
 
         def _wait_for_elapsed():