Clear correct guard

Change-Id: I3f3ab91c10f3077d61a8fd0c351be75cf2e63963
Reviewed-on: https://gerrit.libreoffice.org/70375
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>

framework/source/layoutmanager/toolbarlayoutmanager.cxx

@@ -3771,7 +3771,7 @@ void SAL_CALL ToolbarLayoutManager::closed( const lang::EventObject& e )
         SolarMutexClearableGuard aReadLock;
         bool bLayoutDirty = m_bLayoutDirty;
         LayoutManager* pParentLayouter( m_pParentLayouter );
-        aWriteLock.clear();
+        aReadLock.clear();
 
         if ( bLayoutDirty && pParentLayouter )
             pParentLayouter->requestLayout();