oslo.context is storing a global thread-local variable which keeps the
request context for the current thread. If oslo.context is imported
before calling monkey_patch(), then this thread-local won't be green and
instead of having one request per green thread, we will have one request
object which will be overwritten every time when a new context is
created.
To workaround the problem, always reload oslo_context.context after
calling monkey_patch() to make sure it uses green thread locals.
Change-Id: Id059e5576c3fc78dd893fde15c963e182f1157f6
Closes-Bug: #1773102
233ea582f7