Explicitly copy KDB vtable fields

In preparation for bumping the kdb_vftabl minor version, use explicit
field assignments when copying the module vtable to the internal copy,
so that we can conditionalize assignments for minor versions greater
than 0.

https://github.com/krb5/krb5/commit/50605efa5058583667227223a75ca44a512f4796
Author: Greg Hudson <ghudson@mit.edu>
Commit: 50605efa5058583667227223a75ca44a512f4796
Branch: master
 src/lib/kdb/kdb5.c |   79 ++++++++++++++++++++++++++++++++++++++--------------
 1 files changed, 58 insertions(+), 21 deletions(-)