Remove some objects from the objects pool. Fixes race condition.

Since the central widget would access the local help manager in
its destructor, we need to handle deletion of the objects ourself.
The object pool would release it to early, thus we could never
write some settings back into the collection file.

Change-Id: Ib4e003214d9d0b32bee3922dd23d27624b5d110e
Reviewed-by: Eike Ziller <eike.ziller@nokia.com>