clang-cl loplugin: cppuhelper

Change-Id: I03d082bb6e403bda0028286d89e22006578da4a8
Reviewed-on: https://gerrit.libreoffice.org/29873
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

cppuhelper/source/weak.cxx

@@ -203,7 +203,7 @@ void SAL_CALL OWeakConnectionPoint::removeReference(const Reference< XReference
 // Accidentally occurs in msvc mapfile = > had to be outlined.
 OWeakObject::OWeakObject()
     : m_refCount( 0 ),
-      m_pWeakConnectionPoint( 0 )
+      m_pWeakConnectionPoint( nullptr )
 {
 }
 #endif