For alias properties a binding to the original property
was not properly enabled.
This means that if bindings were reseted the original value from the binding
was overwriting any change to this property.

Solution: We disable the binding of the alias property manually using the
hash from resetBinding().

Task-number: QTCREATORBUG-9582
Change-Id: I7a891bbdd06154de8a4e1ff2d3c0939d4e8b4010
Reviewed-by: Marco Bubke <marco.bubke@digia.com>