Remove the solution when reopening a closed ticket

[marien-probesys]

Problem

Today, when reopening a closed ticket with a solution, the status is set to "in progress" but the solution still exists. This is a weird case because it's impossible to add a new answer.

Solution

We could allow to always add a solution if the status is not finished, but I believe that if we reopen a closed ticket, it's because the solution doesn't work anymore. This needs a confirmation though.