There is no way in PAM_KRB5 to delete the credential of the user on logout, this patch gives a way to do it on session close, if the delete_credential argument is gave to pam_krb5 in session section.
Created attachment 79849 [details] patch
That's not the case for pam_krb5-20030601, though, which deletes credentials on logout.
Marking dupe of the bump bug, as there seems to be lots of issues with the current version, and a new one should be put in tree to allow validating this kind of problems. *** This bug has been marked as a duplicate of 26509 ***