After commit from 2015-06-18 the sortindex was computed slightly
different. In some cases the parent was not deproxied anymore and
therefore the parent.childNodes always returned the empty list of the
proxy object instead of returning the actual childrens list.
Fix sortindex computation in TaxonNode
After commit from 2015-06-18 the sortindex was computed slightly
different. In some cases the parent was not deproxied anymore and
therefore the parent.childNodes always returned the empty list of the
proxy object instead of returning the actual childrens list.