r15481: Update heimdal/ to match current lorikeet-heimdal.

r15481: Update heimdal/ to match current lorikeet-heimdal.

This includes many useful upstream changes, many of which should
reduce warnings in our compile.

It also includes a change to the HDB interface, which removes the need
for Samba4/lorikeet-heimdal to deviate from upstream for hdb_fetch().
The new flags replace the old entry type enum.

(This required the rework in hdb-ldb.c included in this commit)

Andrew Bartlett
(This used to be commit ef5604b87744c89e66e4d845f45b23563754ec05)