krb5: new tag krb5-1.13.6-final

[Tom Yu]

A new lightweight tag "krb5-1.13.6-final" has been created in the krb5
repository for the following commit:

commit 68237c615782cc5fd0bc372e1fa24426399ab520
Author: Tom Yu <tlyu at mit.edu>
Date:   Fri Jul 22 16:32:21 2016 -0400

    Updates for krb5-1.13.6