inline SfxPoolItem copy constructor

as delegating constructor.
In preparation to remove default able copy constructors
of derived classes.

Change-Id: I516efa70ef2a06079194aafbf630e151138c6bbc
Reviewed-on: https://gerrit.libreoffice.org/42923
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Jochen Nitschke <j.nitschke+logerrit@ok.de>

include/svl/poolitem.hxx

@@ -137,7 +137,8 @@ private:
 
 protected:
                              explicit SfxPoolItem( sal_uInt16 nWhich = 0 );
-                             SfxPoolItem( const SfxPoolItem& );
+                             SfxPoolItem( const SfxPoolItem& rCopy)
+                                 : SfxPoolItem(rCopy.m_nWhich) {}
 
 public:
     virtual                  ~SfxPoolItem();

svl/source/items/poolitem.cxx

@@ -35,13 +35,6 @@ SfxPoolItem::SfxPoolItem(sal_uInt16 const nWhich)
 }
 
 
-SfxPoolItem::SfxPoolItem( const SfxPoolItem& rCpy )
-    : m_nRefCount(0) // don't copy that
-    , m_nWhich(rCpy.m_nWhich)
-    , m_nKind(SfxItemKind::NONE)
-{}
-
-
 SfxPoolItem::~SfxPoolItem()
 {
     assert((m_nRefCount == 0 || m_nRefCount > SFX_ITEMS_MAXREF)