Authentication after Disable/Re-enable of ONU fails eventually

Authentication fails after disabling/re-enabling the ONU intermittently. May work the first time you disable/re-enable, but may not work if you do it more times. When it fails, we noticed that eapol packets never make it to VOLTHA. 

Noticed that VOLTHA omci state does not always go back to "tech profile config download success" state after re-enable. Sometimes it is in "initial-mib-download-success" state, sometimes it is in "omci-flows-deleted" state. May not be the real problem but worth mentioning.

Steps in SEBA (can be reproduced without NEM as well by using VOLTHA cli):

• Add ONU that is in the whitelist, add corresponding subscriber
• Perform authentication/DHCP/Ping which is successful in this case
• Admin Disable the ONU --> change ONU's location or remove ONU from the whitelist or use VOLTHA cli to disable ONU device; omci state goes to 'admin-lock'
• Enable the ONU back --> put back ONU's location or re-add ONU to the whitelist or use VOLTHA cli to re-enable ONU device; omci state starts again with "restarting-omci"
• Perform authentication, auth succeeds here and pings work again
• Perform Admin Disable again and Enable the ONU
• Perform authentication , auth fails