Fix super annoying Python 2.6 multiprocessing.Queue stack trace in CI (#72604)

* Fix super annoying Python 2.6 multiprocessing.Queue stack trace in CI

A bug exists in Python 2.6 that sometimes raises an exception during interpreter shutdown. We
encounter this frequently in our CI since we run tests on CentOS 6 as the control node, which
has Python 2.6.6 with this bug.

This PR adds a very minor sleep only on Python 2.6 which gets around this issue. I did lot of testing
using a standalon script I found that easily duplicated the issue to find the minimum sleep value
needed to avoid this issue.

CPython issue: https://bugs.python.org/issue4106
Fix in CPython: https://hg.python.org/cpython/rev/d316315a8781

* Use correct attribute

changelogs/fragments/py26-multiprocess-queue-bug.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - account for bug in Python 2.6 that occurs during interpreter shutdown to avoid stack trace

lib/ansible/executor/task_queue_manager.py

@@ -20,6 +20,7 @@ from __future__ import (absolute_import, division, print_function)
 __metaclass__ = type
 
 import os
+import sys
 import tempfile
 import threading
 import time
@@ -328,6 +329,22 @@ class TaskQueueManager:
         self._final_q.close()
         self._cleanup_processes()
 
+        # A bug exists in Python 2.6 that causes an exception to be raised during
+        # interpreter shutdown. This is only an issue in our CI testing but we
+        # hit it frequently enough to add a small sleep to avoid the issue.
+        # This can be removed once we have split controller available in CI.
+        #
+        # Further information:
+        #     Issue: https://bugs.python.org/issue4106
+        #     Fix:   https://hg.python.org/cpython/rev/d316315a8781
+        #
+        try:
+            if (2, 6) == (sys.version_info[0:2]):
+                time.sleep(0.0001)
+        except (IndexError, AttributeError):
+            # In case there is an issue getting the version info, don't raise an Exception
+            pass
+
     def _cleanup_processes(self):
         if hasattr(self, '_workers'):
             for attempts_remaining in range(C.WORKER_SHUTDOWN_POLL_COUNT - 1, -1, -1):