I was debugging something else and watching

journalctl -f

I came across this line -

org.gnome.evolution.dataserver.Sources3[2437]: AUTH (1392343959.2405.6@nilesh-pc): Initiated

I had no accounts in evolution, but I added and removed an account and that seems to have helped. May be that's the culprit in your case too.

I was debugging something else and watching

journalctl -f

I have this problem too. I came across this line -

org.gnome.evolution.dataserver.Sources3[2437]: AUTH (1392343959.2405.6@nilesh-pc): Initiated

I had no accounts in evolution, but I added and removed an account and that seems to have helped. May be that's the culprit in your case too.

So, it may be wise to check for journal to see if any application is trying to do AUTH if you want to find why a AUTH dialogue is popping up.