Regression: Misleading and inconsistent diff when having staged and unstaged changes in git

1. Open a file which is checked in to git.
2. Add a line to the file and save it.
3. Select "Tools" -> "Git" -> "Current File" -> "Stage ... for Commit" from the menu.
4. Select "Tools" -> "Git" -> "Current File" -> "Diff of ..." from the menu.
   Creator does not display any changes.
5. Add another line to the file and save it again.
6. Select "Tools" -> "Git" -> "Current File" -> "Diff of ..." from the menu.
   Creator displays both, the staged and the unstaged change.

"Diff" in Creator should display the same as "git diff" on the command line would do, i.e. only unstaged changes. In 2.7 this used to work correctly.