fix for windows build

after my commit 032dae36
"use unique_ptr for pImpl in sfx2/"

Change-Id: Ib7361a6b030a8ed28383bf0d30935bd3fb4a397d

sfx2/source/appl/lnkbase2.cxx

@@ -192,7 +192,7 @@ static DdeTopic* FindTopic( const OUString & rLinkName, sal_uInt16* pItemStt )
 }
 
 SvBaseLink::SvBaseLink( const OUString& rLinkName, sal_uInt16 nObjectType, SvLinkSource* pObj )
-    : pImpl(0)
+    : pImpl()
     , m_bIsReadOnly(false)
 {
     bVisible = bSynchron = bUseCache = true;