preCICE mesh id (-1) error (OpenFOAM+CalculiX CHT)

Hi,

I am able to reproduce the error.

 ---[precice] ERROR:  The given Mesh ID "-1" is unknown to preCICE.

I have commented in the PR https://github.com/precice/tutorials/pull/104 to try and resolve this issue. I believe it is because Heat-Flux works on the face centres, but in this case we have only defined the nodes of the mesh.