An additional complication with the kadm5 sonames

[Sam Hartman]

At least in Debian, Heimdal is currently using libkadm5clnt.so.7 and
libkadm5srv.so.8.

Based on that I think a rename to libkadm5clnt-mit.so.7 would be better,
but I'm happy with any solution that works.

Also, in the interest of completeness, Debian policy provides somewhat
more flexibility than I thought here.  I could potentially implement a
solution where the libraries live in a different directory from the
Heimdal libraries.  I don't think that would be the correct technical
solution, but since I said that was not possible and later learned it
was, I wanted to disclose my error.