Bug 38243: Remove DT's header_filter custom param

Bug 38243: Remove DT's header_filter custom param

It seems to be a leftover from bug 32401, the code does not make sense:

 569                 if(options.header_filter) {
 570                     options.query_parameters = query_parameters;
 571                 } else {
 572                     dataSet.q = query_parameters;
 573                     delete options.query_parameters;
 574                 }

Then options.query_parameters is never used.

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>