Create metadata fails when no densification product list is defined

densification_path_list is not initialized when no densification is used.

changed milestone to %1.6.2

added bug label

created merge request !41 (merged) to address this issue

mentioned in merge request !41 (merged)

mentioned in commit 6f76edd1

mentioned in commit f83192ca

mentioned in merge request !44 (merged)

closed via merge request !44 (merged)

mentioned in commit 4521f7d3

mentioned in merge request !45 (merged)

mentioned in commit 99902a55

mentioned in commit 14922e57