Comment 10 for bug 1130326

A workaround based on keith (alclsdkrak1) workaround in #1168293 :

Enter network details as normal using the network manager but select a random certificate so the dialog is not displayed.

The connection will fail due to the fake certificate

Disable WiFi

cd /etc/NetworkManager/system-connections

sudo nano SSID #this is the name of the SSID ie eduroam

Remove the lines :
ca-cert=/path/to/random/certificate/randomcert.pem
system-ca-certs=true

save the file

enable WiFi

connect successfully

Hope this helps someone