krb5: new tag krb5-1.15.1-final

[Greg Hudson]

A new lightweight tag "krb5-1.15.1-final" has been created in the krb5
repository for the following commit:

commit b9ad6c49505c96a088326b62a52568e3484f2168
Author: Greg Hudson <ghudson at mit.edu>
Date:   Tue Feb 28 14:51:29 2017 -0500

    Update for krb5-1.15.1