i.e. follow up to

commit 465359c3
Author: Michael Stahl <mstahl@redhat.com>
Date:   Wed Mar 11 16:39:24 2015 +0100

    do not call virtual Commit() from dtors of utl::ConfigItem subclasses

    ~SvtAppFilterOptions_Impl() demonstrates that this is a bad idea, by not
    invoking its subclasses' ImplCommit() but its own.

to avoid assert in SvtSearchOptions dtor

Change-Id: I0eaf93450e1daddb81a9463f2c1df48a334dfb22