KFileItemModel: Delay emitting currentDirectoryRemoved() signal
The KCoreDirLister object is modified before KCoreDirListerCache::deleteDir()
returns because the signal currentDirectoryRemoved() is emitted.
This prevents removal of the deleted lister from dirData.listersCurrentlyHolding
in KCoreDirListerCache::forgetDirs() when the tab is closed, which causes the
crash described in the bug. Hence, the signal currentDirectoryRemoved()
is delayed to ensure this does not occur.