Do not keep an open file around when passing the file name to the
editor. The editor won't be able to save on windows since the file
is locked.

Task-number: QTCREATORBUG-5972
Change-Id: Ib424c76d2e3e57d43fdc1e1c222dbeb148669038
Reviewed-by: Hugues Delorme <delorme.hugues@fougsys.fr>