Modernize the test testNavigationRootDoesNotOverrideExplicitPath

The test was still assuming that the navigation root configuration
is stored in the portal properties while it is in the registry since
quite some time.

Adapt the test to check that nothing breaks when tweaking the registry.

Refs. #125

Products/CMFPlone/tests/testQueryCatalog.py

@@ -133,10 +133,14 @@ def testNavigationRoot(self):
 
     def testNavigationRootDoesNotOverrideExplicitPath(self):
         request = {'SearchableText': 'a*', 'path': '/yyy/zzz'}
-        ntp = self.portal.portal_properties.navtree_properties
         self.setRoles(('Manager',))
         self.portal.invokeFactory('Folder', 'foo')
-        ntp.root = '/foo'
+        registry = getUtility(IRegistry)
+        navigation_settings = registry.forInterface(
+            INavigationSchema,
+            prefix='plone'
+        )
+        navigation_settings.root = '/'
         qry = self.folder.queryCatalog(request, use_navigation_root=True)
         self.assertEqual('/yyy/zzz', qry['path'])