(ITS#5052) slapadd -q can create invalid index

[hyc@OpenLDAP.org]

Full_Name: Howard Chu
Version: 2.3.x
OS: 
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (204.95.127.34)
Submitted by: hyc


On a database with a zero-length suffix, slapadd and slapindex in quick mode can
erroneously generate index records for the context entry, which has an entry ID
of zero. The entry ID zero is normally invalid in an index, and is always
filtered out of index operations, but the quick mode indexer didn't exclude it
as it should.