Qt: do not leak ActionsManager on exit.

modules/gui/qt4/main_interface.cpp

@@ -31,6 +31,7 @@
 
 #include "main_interface.hpp"
 #include "input_manager.hpp"
+#include "actions_manager.hpp"
 
 #include "util/customwidgets.hpp"
 #include "util/qt_dirs.hpp"
@@ -249,6 +250,8 @@ MainInterface::~MainInterface()
         delete playlistWidget;
     }
 
+    ActionsManager::killInstance();
+
     settings->beginGroup( "MainWindow" );
 
     settings->setValue( "pl-dock-status", (int)i_pl_dock );