Dx siteroot (#60)

Fixed test that failed for dexterity site root.

Co-authored-by: ale-rt <alessandro.pisa@gmail.com>

src/plone/app/testing/layers.rst

@@ -338,7 +338,7 @@ We can now look for this new object through the server.
     ['http', '//localhost']
 
     >>> from six.moves.urllib.request import urlopen
-    >>> conn = urlopen(portal_url + '/Title', timeout=10)
+    >>> conn = urlopen(portal_url, timeout=10)
     >>> responseBody = conn.read()
     >>> b"Fancy Portal" in responseBody
     True