Cdbext: remove the depth limitation of symbol dump.

This allows us to print expanded locals and expressions hierarchys
while stepping through the source.

Change-Id: I0971cadfd0eed807ae2d3f9fd21bff48daad5175
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: hjk <hjk121@nokiamail.com>