krb5: new tag krb5-1.12.3-final

[Tom Yu]

A new lightweight tag "krb5-1.12.3-final" has been created in the krb5
repository for the following commit:

commit a956edbc87735c8c8f6df2dbddd1c0f75020e2a5
Author: Tom Yu <tlyu at mit.edu>
Date:   Wed Feb 18 16:23:49 2015 -0500

    Updates for krb5-1.12.3