Don't store the current root tiles
requested to merge work/mart/dontStoreRootTile into work/zzag/quick-tiling-fix-multi-screen-navigation
m_rootTile and m_quickRootTile can be temporarly out of sync if they are updated via a signal getting those calls wrong if they are invoked between currentdesktopchanged emission and the signal handler in virtualdesktopmanager
make rootTile() and quickRootTile() always return the proper root by taking it indexed by VirtualDesktopManager::self()->currentDesktop()
Edited by Marco Martin