Bug in chunking header/footer generation

[Jens Stavnstrup <js@ddre.dk>]

In DocBook XSL 1.62.4 I observe the following behaviour, but suspect
this to be a bug, which have existed for a long time.

When a document contains an index. The chunk mechanism by default generate 
a chunk (or more ??) containing this index.

When generate.index is set to 0, this index is as expected not generated. 
However the previous section header and footer, will still have a "next" 
reference to the non-existing index.

Regards,

Jens