File name in save dialog defaults to directory name

If QFileDialog::getSaveFileName() is passed an empty string for the directory path, the default file name in the "Save As" field is the name of the directory.

The default file name should be empty. This was the behavior in Qt 4.8.1.

It's easy to see the regression if you compare examples/dialogs/standarddialogs. In both versions, the "QFileDialog::getSaveFileName()" button pops up a save dialog that is (for me) initially in a directory called "MacOS". In Qt 4.8.1, the "Save As" field is empty. In Qt 5.1.0-beta1, the "Save As" field says "MacOS".