Fixes a regression introduced by 6af0dad2eeba.
DolphinViewContainer::setActive() unconditionally calls setActive() on
the url navigator, view and search box. However this has side effects,
as DolphinSearchBox activates itself if it receives a FocusIn event.
This is what happens in the bug:
1. The searchbox of the first tab gets disactivated (as side effect of
disactivating its container).
2. Second tab gets closed, we call removeTab(1) in the tab widget.
3. The searchbox of the first tab gets a FocusIn event and calls
setActive(true).
4. Since it was disactivated, it emits activated() and this results in the
activeViewChanged() signal which causes the crash, because
the currentIndex() of the tab page is still 1 but its widget has
already been invalidated.
This patch temporarily disables the activeViewChanged signal in DolphinTabWidget,
so that the crash in step 4. does not happen anymore.
BUG: 379135
FIXED-IN: 17.04.2