Possible double includes in issue query in gantt helper
include line source:/tags/3.4.0/lib/redmine/helpers/gantt.rb#L141 should not be needed anymore as per r16221. It will not cause any problems currently, but should for example the sort options include any of the included relations, this might lead to ambiguous names in the
JOIN statements leading to an error in the sorting.
This affects all versions since 3.4.0