Adding method definition to .cu file doesn't work

When editing a C++ class, it's possible to add a function in the header file and then press Alt + Enter. A menu will popup which allows to add the definition to the .cpp file.

This doesn't work for .cu (CUDA) files currently, but it did work in earlier versions, for instance 2.8.1 (maybe after doing http://rodolphe-vaillant.fr/?e=1). I suppose that somebody attempted to further improve QTCREATORBUG-694, but unintentionally broke this possibility. So maybe add a comment

edit: it happened in commit 5a3a940ad3b3984b308b539e7f0456ce11d4d90e (Use new mime database)

Anyway, I tried to fix it, see the attached patch, and it worked.