This tests switching link integrity checking on and off.  First we need to
set up the necessary links:

  >>> self.setRoles(('Manager',))
  >>> self.setText(portal.doc1, '<a href="doc2">a document</a>')

Next we try to delete the referenced document.  Before we can do this we need
to prevent the test framework from choking on the exception we intentionally
throw (see docs/testRemovalTriggersConfirmation.txt for more info):

  >>> self.setStatusCode('LinkIntegrityNotificationException', 200)
  >>> browser = self.getBrowser(loggedIn=True)
  >>> browser.open('http://nohost/plone/folder_contents')
  >>> browser.getControl('Test Page 2').selected = True
  >>> browser.getControl('Delete').click()
  >>> browser.contents
  '...<form ... action="http://nohost/plone/removeConfirmationAction">...
   ...<a href="http://nohost/plone/doc2"...Test Page 2...
   ...This...Document...is referenced by the following items:...
   ...<li>...href="http://nohost/plone/doc1"...Test Page 1...</li>...
   ...Would you like to delete it anyway?...'

Now we turn the switch for link integrity checking off via the site
properties and try again:

  >>> props = portal.portal_properties.site_properties
  >>> props.manage_changeProperties(enable_link_integrity_checks=False)
  >>> browser.reload()
  >>> browser.url
  'http://nohost/plone/...folder_contents'
  >>> browser.contents
  '...<dl class="portalMessage...Item(s) deleted...</dl>...'

The document should have been deleted:

  >>> portal.doc2
  Traceback (most recent call last):
  ...
  AttributeError: doc2

