delete operators properly

Change-Id: Ia917b70712717387aa8d7a17334efd41931bdb88
Reviewed-on: https://gerrit.libreoffice.org/47087Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

sd/inc/OutlinerIterator.hxx

@@ -274,7 +274,7 @@ private:
 
     // Do not allow default constructor and copying of outliner containers.
     OutlinerContainer (const OutlinerContainer&) = delete;
-    OutlinerContainer& operator= (const OutlinerContainer&) {return *this;};
+    OutlinerContainer& operator= (const OutlinerContainer&) = delete;
 };
 
 /** Data collection specifying a <type>SdrObject</type> and its position in

sd/source/ui/inc/OutlinerIteratorImpl.hxx

@@ -206,7 +206,7 @@ private:
     SdrObjListIter* mpObjectIterator;
 
     // Don't use this operator.
-    ViewIteratorImpl& operator= (const ViewIteratorImpl&){return *this;};
+    ViewIteratorImpl& operator= (const ViewIteratorImpl&) = delete;
 };
 
 /** Iterator for iteration over all objects in all views.  It automatically
@@ -235,7 +235,7 @@ private:
     sal_Int32 mnPageCount;
 
     // Don't use this operator.
-    DocumentIteratorImpl& operator= (const DocumentIteratorImpl& ){return *this;};
+    DocumentIteratorImpl& operator= (const DocumentIteratorImpl& ) = delete;
 };
 
 } } // end of namespace ::sd::outliner