DolphinTreeView contains some code to update the selection after a

DolphinTreeView contains some code to update the selection after a
keyboard search because QTreeView (unlike the other item views) does
not handle this internally.

This commit simplifies that code by performing the selection update in
the method keyboardSearch(). That way, we can get rid of the member
m_updateCurrentIndex and of 3 member functions. The unit tests still
pass, so I'm quite confident that this does not break anything.

svn path=/trunk/KDE/kdebase/apps/; revision=1214865