ovdb connections fail. out-of-sync with ovs library

[surlyjake]

steps to reproduce:
1. Follow documentation for establishing an ovsdb connection to a bridge https://docs.openstack.org/os-ken/latest/library_ovsdb_manager.html?highlight=ovsdb. save example file as ovsdb-test.py

2. execute venv/bin/osken-manager.py ovsdb-test.py

Expected output:
MyApp Ken app should log
'New OVSDB connection from system-id=....., address=....'

Actual Output:

yieldd an error when the bridge connects:

Listening on 0.0.0.0:6640 for clients
hub: uncaught exception: Traceback (most recent call last):
  File "/home/ubuntu/venv/lib/python3.8/site-packages/os_ken/lib/hub.py", line 69, in _launch
    return func(*args, **kwargs)
  File "/home/ubuntu/venv/lib/python3.8/site-packages/os_ken/services/protocols/ovsdb/manager.py", line 145, in _start_remote
    app = client.RemoteOvsdb.factory(sock, client_address,
  File "/home/ubuntu/venv/lib/python3.8/site-packages/os_ken/services/protocols/ovsdb/client.py", line 329, in factory
    system_id = discover_system_id(idl)
  File "/home/ubuntu/venv/lib/python3.8/site-packages/os_ken/services/protocols/ovsdb/client.py", line 125, in discover_system_id
    idl.run()
  File "/home/ubuntu/venv/lib/python3.8/site-packages/ovs/db/idl.py", line 432, in run
    self.send_cond_change()
  File "/home/ubuntu/venv/lib/python3.8/site-packages/ovs/db/idl.py", line 642, in send_cond_change
    if not self._session.is_connected() or self._request_id is not None:
AttributeError: 'Idl' object has no attribute '_request_id'

versions:
os-ken==2.6.0
ovs==3.1.2

This appears to be related to wrapping of the OVS library's Idl class in os_ken/services/protocols/ovsdb/client.py. The ovs library Idl class has been updated and the Ken-wrapped class isn't compatible with changes to the OVS Idl class.

Here are some issues related to incompatabilities between the ryu/ken idl wrapper and upstream ovs codebase which have been reported against the Ryu codebase prior to the os-ken fork which :
1. https://github.com/faucetsdn/ryu/issues/146
2. https://github.com/faucetsdn/ryu/issues/157
3. https://<email address hidden>/msg08158.html

Workarounds:
downgrading to ovs version 2.10 appears to work at least as far as establishing the ovsdb initial connection.
  pip install ovs=2.10