Installing or Upgrading to OpenShift 3.10/3.11 Fails with "AttributeError: {{ openshift_metrics_heapster_nodeselector | map_to_pairs }}: 'unicode' object has no attribute 'iteritems'"

Issue

While trying to install or upgrade to OpenShift 3.10 or 3.11, I am seeing the following error:

The full traceback is:
Traceback (most recent call last):
  File "/usr/lib/python2.7/site-packages/ansible/executor/task_executor.py", line 148, in run
    res = self._execute()
  File "/usr/lib/python2.7/site-packages/ansible/executor/task_executor.py", line 495, in _execute
    self._task.post_validate(templar=templar)
  File "/usr/lib/python2.7/site-packages/ansible/playbook/task.py", line 249, in post_validate
    super(Task, self).post_validate(templar)
  File "/usr/lib/python2.7/site-packages/ansible/playbook/base.py", line 377, in post_validate
    value = templar.template(getattr(self, name))
  File "/usr/lib/python2.7/site-packages/ansible/template/__init__.py", line 494, in template
    disable_lookups=disable_lookups,
  File "/usr/lib/python2.7/site-packages/ansible/template/__init__.py", line 450, in template
    disable_lookups=disable_lookups,
  File "/usr/lib/python2.7/site-packages/ansible/template/__init__.py", line 672, in do_template
    res = j2_concat(rf)
  File "<template>", line 9, in root
  File "/usr/lib/python2.7/site-packages/ansible/template/__init__.py", line 204, in resolve_or_missing
    val = super(AnsibleContext, self).resolve_or_missing(key)
  File "/usr/lib/python2.7/site-packages/Jinja2-2.10-py2.7.egg/jinja2/runtime.py", line 217, in resolve_or_missing
    return resolve_or_missing(self, key)
  File "/usr/lib/python2.7/site-packages/Jinja2-2.10-py2.7.egg/jinja2/runtime.py", line 129, in resolve_or_missing
    return context.parent[key]
  File "/usr/lib/python2.7/site-packages/ansible/template/vars.py", line 108, in __getitem__
    raise type(e)(to_native(variable) + ': ' + e.message)
AttributeError: {{ openshift_metrics_heapster_nodeselector | map_to_pairs }}: 'unicode' object has no attribute
'iteritems'