HEADS-UP: Indexing Change

["Kurt D. Zeilenga" <Kurt@OpenLDAP.org>]

I just replaced the hash function used in index generation
for performance reasons (HEAD branch only).  The old code
used MD5 namely because we had it available.  MD5 is too slow.
The new hash is a Fowler/Noll/Vo algorithm (32-bit FNV-1)
and is quite fast and should work well across most data sets.
It may be replaced with a 64-bit version at a later date
(the 32-bit version is 64-bit safe).

This change will require rebuilding of databases....

Kurt