Debugger: Simplify QVariant dumper

Change-Id: I107ee6ccbca3a588c05647a4158affc8aa307c70
Reviewed-by: hjk <hjk121@nokiamail.com>
BlackBerry: Fix compile with Qt4

Change-Id: Ib3ccf13badf710afc95cccbbab6d6b01d9a00e6a
Reviewed-by: Mehdi Fekari <mfekari@blackberry.com>
Reviewed-by: Christian Kandeler <christian.kandeler@digia.com>