get_hub function was added in commit b155da42 with the idea to bypass
eventlet automatic hub selection that prefers epoll if available by default.
Since version 0.20.0 eventlet removed select.poll() function in its patched
select module (eventlet.green.select), see:
- https://github.com/eventlet/eventlet/commit/614a20462
So if eventlet monkey patching is done before a get_hub() call (as now in
wsgi.py since commit c9410c7d) if we use 'import select' we get the eventlet
version that don't have poll attribute.
To prevent that we use eventlet.patcher.original function to get python select
module to test if poll() is available on current platform.
Change-Id: I69b3db3951b3d3b6583845978deb2883492e7f0f
Closes-Bug: 1804627
(cherry picked from commit 4809884d9f)
8eba4f8c8f