Can't establish BGP session with password authentication

Creating a neutron BGP peer with password authentication leads to an error reported on neutron-bgp-dragent.log.

2020-10-06 18:58:51.861 125213 DEBUG bgpspeaker.peer [-] Started peer Peer(ip: 100.94.2.2, asn: 65200) _run /usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/peer.py:676
2020-10-06 18:58:51.861 125213 DEBUG bgpspeaker.peer [-] start connect loop. (mode: active) _on_update_connect_mode /usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/peer.py:582
2020-10-06 18:58:52.862 125213 DEBUG bgpspeaker.peer [-] Peer 100.94.2.2 BGP FSM went from Idle to Connect bgp_state /usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/peer.py:236
2020-10-06 18:58:52.863 125213 DEBUG bgpspeaker.peer [-] Peer(ip: 100.94.2.2, asn: 65200) trying to connect to ('100.94.2.2', 179) _connect_loop /usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/peer.py:1292
2020-10-06 18:58:52.863 125213 DEBUG bgpspeaker.base [-] Connect TCP called for 100.94.2.2:179 _connect_tcp /usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/base.py:412
2020-10-06 18:58:52.864 125213 ERROR os_ken.lib.hub [-] hub: uncaught exception: Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/os_ken/lib/hub.py", line 69, in _launch
    return func(*args, **kwargs)
  File "/usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/peer.py", line 1296, in _connect_loop
    self._connect_tcp(peer_address, File "/usr/lib/python3/dist-packages/os_ken/services/protocols/bgp/base.py", line 422, in _connect_tcp
    sockopt.set_tcp_md5sig(sock, peer_addr[0], password) File "/usr/lib/python3/dist-packages/os_ken/lib/sockopt.py", line 71, in set_tcp_md5sig
    impl(s, addr, key) File "/usr/lib/python3/dist-packages/os_ken/lib/sockopt.py", line 38, in _set_tcp_md5sig_linux
    sa = sockaddr.sa_in4(addr) File "/usr/lib/python3/dist-packages/os_ken/lib/sockaddr.py", line 63, in sa_in4
    return _pad_to(hdr + data, _SIN_SIZE) File "/usr/lib/python3/dist-packages/os_ken/lib/sockaddr.py", line 57, in _pad_to
    return data + pad_len * '\0'
TypeError: can't concat str to bytes

The log is reported after peer is created and associated to speaker.
Ex.:

#openstack bgp speaker create --ip-version 4 --local-as 65211 --no-advertise-floating-ip-host-routes bgpspeaker
#openstack bgp speaker add network bgpspeaker provider-network
#openstack bgp peer create --peer-ip 100.94.2.2 --remote-as 65200 --auth-type md5 --password cisco bgppeer
#openstack bgp speaker add peer bgpspeaker bgppeer
#openstack bgp dragent add speaker 27f6b5bc-4b0d-466c-957e-34059bd2cc2b bgpspeaker

If you create a BGP peer without password, everything works just fine.

Opesntack version: Ussuri
Deployed using Juju
Distro: Ubuntu Focal Fossa
The environment is a full deployment with all core services running in multi-node.

This looks a lot with the already reported and fixed bug #1592982.