krb5: new tag krb5-1.12.4-final

[Tom Yu]

A new lightweight tag "krb5-1.12.4-final" has been created in the krb5
repository for the following commit:

commit bb4252d1fcf25ea55db923f0cb868d498695e288
Author: Tom Yu <tlyu at mit.edu>
Date:   Fri May 29 15:15:55 2015 -0400

    Updates for krb5-1.12.4