Upgrade of aggregated logging fails with "Cannot allocate memory".

Issue

• Upgrade of aggregated logging fails with "Cannot allocate memory":

TASK [openshift_logging_fluentd : Label infrahost.example.com for Fluentd deployment] ***************************************
task path: /usr/share/ansible/openshift-ansible/roles/openshift_logging_fluentd/tasks/label_and_wait.yaml:2
ERROR! Unexpected Exception, this is probably a bug: [Errno 12] Cannot allocate memory
the full traceback was:

Traceback (most recent call last):
  File "/usr/bin/ansible-playbook", line 106, in <module>
    exit_code = cli.run()
  File "/usr/lib/python2.7/site-packages/ansible/cli/playbook.py", line 122, in run
    results = pbex.run()
  File "/usr/lib/python2.7/site-packages/ansible/executor/playbook_executor.py", line 154, in run
    result = self._tqm.run(play=play)
  File "/usr/lib/python2.7/site-packages/ansible/executor/task_queue_manager.py", line 290, in run
    play_return = strategy.run(iterator, play_context)
  File "/usr/lib/python2.7/site-packages/ansible/plugins/strategy/linear.py", line 277, in run
    self._queue_task(host, task, task_vars, play_context)
  File "/usr/lib/python2.7/site-packages/ansible/plugins/strategy/__init__.py", line 254, in _queue_task
    worker_prc.start()
  File "/usr/lib64/python2.7/multiprocessing/process.py", line 130, in start
    self._popen = Popen(self)
  File "/usr/lib64/python2.7/multiprocessing/forking.py", line 121, in __init__
    self.pid = os.fork()
OSError: [Errno 12] Cannot allocate memory