QtIFW

Fix crash while canceling the meta data unzip task.

The crash happens cause in reset we do a delete later on the
unzip tasks and then a second delete while not checking early
enough for the set error code.

Change-Id: Iee17cd6863435d25c0c999fb0cc4e05672de3cc8
Reviewed-by: Kai Koehne <kai.koehne@digia.com>