If the <provision_dir>/private/tls dir is not present, samba tries to create a selfsigned certificate and should fail (because it can't store it in the tls dir).
But instead it says:
TLS self-signed keys generated OK
The following line tells us more about the real situation:
GNUTLS failed to initialise - Error while reading file.
You can assign this bug to me, I started it just not to forget.
I think you should be able to do it yourself, aren't you? (You just need to put your account email address into "Reassign bug to" and click on "Commit").
But okay, I do it for you as requested.
Okay, closed by request (http://gitweb.samba.org/samba.git/?p=samba.git;a=commitdiff;h=f8d49958b2a5c55e837ebe903dd5207a92d19d63).