Only allow tasks in a final state to have a finished date

Closes #1884 (closed)

changed milestone to %Arkindex 1.7.1

requested review from @babadie

assigned to @erouchet

added 2 commits

• 9a92975c - 1 commit from branch release-1.7.1
• f2dbdd77 - Only allow tasks in a final state to have a finished date

Compare with previous version

merged