Show "Open containing folder" also for files of qrc nodes.

Task-number: QTCREATORBUG-12374
Change-Id: I9dd8bbf9134bac65fbaa70b0614b27365377b0bf
Reviewed-by: Daniel Teske <daniel.teske@digia.com>
QmlDesigner.Model: Remove unused code

Change-Id: I313c9d5180493d4ea77360c1bf8a5cbb725241e2
Reviewed-by: Marco Bubke <marco.bubke@digia.com>