QmlDesigner: Fix entires for component combobox

Task-number: QTCREATORBUG-10383
Change-Id: Ifa539401c75c82bd3afdec3143f9f17e69a2e36b
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>
QmlDesigner: Fix crash for invalid id

Change-Id: I27bcf6d4ec895a464351502f3d8e9d4ed71cab6d
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>