Fix uninitialised value
Do not read m_hoveredColumnHearderRoleIndex before it has been initialised.
#6 0x00007fe00632182c in QList<KFileItemModel::RoleInfo>::Node::t (this=<optimized out>, this=<optimized out>) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:153
#7 QList<KFileItemModel::RoleInfo>::at (i=3080252, this=0x7ffdf2e9bba8) at /usr/include/x86_64-linux-gnu/qt5/QtCore/qlist.h:572
#8 DolphinView::eventFilter (this=0x5584bef25160, watched=0x5584bef8a300, event=0x7ffdf2e9bd30) at ./src/views/dolphinview.cpp:978
#9 0x00007fe003ebbdda in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#10 0x00007fe004b6c782 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#11 0x00007fe004b75411 in QApplication::notify(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#12 0x00007fe003ebc07a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#13 0x00007fe004b72269 in QApplication::event(QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#14 0x00007fe004b6c793 in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Widgets.so.5
#15 0x00007fe003ebc07a in QCoreApplication::notifyInternal2(QObject*, QEvent*) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#16 0x00007fe003f14e0b in QTimerInfoList::activateTimers() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#17 0x00007fe003f15754 in ?? () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#18 0x00007fe001d20d3b in g_main_context_dispatch () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#19 0x00007fe001d756c8 in ?? () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#20 0x00007fe001d1e3e3 in g_main_context_iteration () from /lib/x86_64-linux-gnu/libglib-2.0.so.0
#21 0x00007fe003f15ad8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#22 0x00007fe003eba99b in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#23 0x00007fe003ec2f34 in QCoreApplication::exec() () from /lib/x86_64-linux-gnu/libQt5Core.so.5
#24 0x00005584bd2a9aad in main (argc=<optimized out>, argv=<optimized out>) at ./src/main.cpp:249