ProjectExplore: Use the filename not displayName for renaming

Those differ for ResourceNodes

Change-Id: I5ef356f65b856d433b98ccf4ca0e185392d0396f
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/projectexplorer/projectmodels.cpp

@@ -278,7 +278,7 @@ QVariant FlatModel::data(const QModelIndex &index, int role) const
             break;
         }
         case Qt::EditRole: {
-            result = node->displayName();
+            result = QFileInfo(node->path()).fileName();
             break;
         }
         case Qt::ToolTipRole: {