Rebase master on krb5 1.10.4 final

Not an actual pull request. Do not merge.

rebase-master-on-krb5-1.10.4-final rebases our code on top of the first stable release that contains the commit that we had to merge in the middle of our project. The project should still compile and run fine (I just tested it on my VM), and is now a linear history on top of a stable release.

Can we replace master with this branch?

We can also look into squashing bad commits, or rebasing on an even newer version of Kerberos, but I wanted to start with this first.