Monkey patch original current_thread _active

Monkey patch the original current_thread to use the up-to-date _active
global variable. This solution is based on that documented at:
eventlet/eventlet#592

Also disable E402 to allow the change in.

Change-Id: I508fcd0707ecdd2bf720303f6cbb4087a38aaadd
Closes-Bug: #1863021

murano/monkey_patch.py

@@ -23,3 +23,9 @@
     eventlet.monkey_patch(os=False)
 else:
     eventlet.monkey_patch()
+# Monkey patch the original current_thread to use the up-to-date _active
+# global variable. See https://bugs.launchpad.net/bugs/1863021 and
+# https://github.com/eventlet/eventlet/issues/592
+import __original_module_threading as orig_threading
+import threading  # noqa
+orig_threading.current_thread.__globals__['_active'] = threading._active

tox.ini

@@ -95,7 +95,8 @@ whitelist_externals = rm
 show-source = true
 builtins = _
 # W605 invalid escape sequence
-ignore = W605,W504,W503,E123,H405
+# E402 fires an error on eventlet import. Should probably remove condition alltogether
+ignore = W605,W504,W503,E123,H405,E402
 exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,build
 
 [hacking]