fix VS contour helper

[kerautret]

PR Description

Fix as mentioned in PR #1381
Not yet tested on VS, I can try next week on the PC of the dept.

Checklist

• Unit-test of your feature with Catch.
• Doxygen documentation of the code completed (classes, methods, types, members...)
• Documentation module page added or updated.
• New entry in the ChangeLog.md added.
• No warning raised in Debug cmake mode (otherwise, Travis C.I. will fail).
• All continuous integration tests pass (Travis & appveyor)

[dcoeurjo]

thx @kerautret , can you please add a Changlog entry ?

[kerautret]

done thanks, btw I started to install a new VS config on the dept computer, not yet finished but probably finished this week.

[dcoeurjo]

@kerautret is this PR complete ?

[kerautret]

It is up to you, I have finished the VS tests but we can merge and add a new issue later, else I will be able to test perhaps tomorrow.

[dcoeurjo]

Let’s merge this one. Thanks