Improve DolphinTreeViewTest's stability.

Improve DolphinTreeViewTest's stability.

When running the test in the background while using the computer for
other things, it may happen that the test's widgets are not focused,
which led to an infinite loop before this commit. I've removed the
checks that caused this loop because the only thing that is important
for the test is that the view loses the keyboard focus at some point
(see bug 220898).

svn path=/trunk/KDE/kdebase/apps/; revision=1215139