improve AttributeState compare operator

guess this was the original intention, else the nullptr checks
would be pointless

Change-Id: Ifb41b125c6d297c76c1d1b5c06c8f9f127b8e613
Reviewed-on: https://gerrit.libreoffice.org/53644Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

forms/source/richtext/rtattributes.hxx

@@ -115,10 +115,10 @@ namespace frm
         if ( !pItemHandleItem && _rRHS.pItemHandleItem )
             return false;
 
-        if ( !pItemHandleItem && !_rRHS.pItemHandleItem )
+        if ( pItemHandleItem == _rRHS.pItemHandleItem )
             return true;
 
-        return pItemHandleItem == _rRHS.pItemHandleItem;
+        return *pItemHandleItem == *_rRHS.pItemHandleItem;
     }
 
     class IMultiAttributeDispatcher