use unique_ptr in xmlhelp

Change-Id: Ic49bb1bc6591735562b0b23d821202bab00ceba2
Reviewed-on: https://gerrit.libreoffice.org/65533
Tested-by: Jenkins
Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk>

xmlhelp/source/cxxhelp/provider/databases.cxx

@@ -808,15 +808,15 @@ Reference< XHierarchicalNameAccess > Databases::jarFile( const OUString& jar,
 
             Sequence< Any > aArguments( 2 );
 
-            XInputStream_impl* p = new XInputStream_impl( zipFile );
+            std::unique_ptr<XInputStream_impl> p(new XInputStream_impl( zipFile ));
             if( p->CtorSuccess() )
             {
-                Reference< XInputStream > xInputStream( p );
+                Reference< XInputStream > xInputStream( p.release() );
                 aArguments[ 0 ] <<= xInputStream;
             }
             else
             {
-                delete p;
+                p.reset();
                 aArguments[ 0 ] <<= zipFile;
             }