Reset the required setting of the author_email widget each time.

Otherwise, the email field might get set to required when an anonymous
user visits, and then remain required when an authenticated user
visits, making it impossible for an authenticated user to fill in the
form without validation error.  Or when in the control panel the field
is set as not required anymore, that change would have no effect until
the instance was restarted.

plone/app/discussion/tests/functional_test_comments.txt

@@ -479,3 +479,60 @@ Make sure the edit was successful.
 
     >>> 'Lorem ipsum' in browser.contents
     True
+
+
+Require anonymous email
+-----------------------
+
+Edit the control panel.
+
+    >>> browser.open(portal_url + '/logout')
+    >>> browser.open(portal_url + '/login_form')
+    >>> browser.getControl(name='__ac_name').value = 'admin'
+    >>> browser.getControl(name='__ac_password').value = 'secret'
+    >>> browser.getControl(name='submit').click()
+    >>> browser.open(portal_url+'/@@discussion-controlpanel')
+    >>> browser.getControl(name='form.widgets.anonymous_email_enabled:list').value = [True]
+    >>> browser.getControl(name='form.buttons.save').click()
+    >>> browser.open(portal_url + '/logout')
+
+Post an anonymous comment without setting the email.
+
+    >>> unprivileged_browser.open(urldoc1)
+    >>> unprivileged_browser.getControl(name='form.widgets.text').value = "This is an anonymous comment without email"
+    >>> unprivileged_browser.getControl(name='form.buttons.comment').click()
+    >>> 'Required input is missing' in unprivileged_browser.contents
+    True
+
+Try again.
+
+    >>> unprivileged_browser.getControl(name='form.widgets.text').value = "This is an anonymous comment with email"
+    >>> unprivileged_browser.getControl(name='form.widgets.author_email').value = "email@example.org"
+    >>> unprivileged_browser.getControl(name='form.buttons.comment').click()
+    >>> 'Required input missing' in unprivileged_browser.contents
+    False
+    >>> 'Your comment awaits moderator approval' in unprivileged_browser.contents
+    True
+
+Posting as member should still work.  Especially it should not
+complain about missing input for an invisible author_email field.
+Login as user 'jim'.
+
+    >>> browser_member.open(portal_url + '/login_form')
+    >>> browser_member.getControl(name='__ac_name').value = 'jim'
+    >>> browser_member.getControl(name='__ac_password').value = 'secret'
+    >>> browser_member.getControl(name='submit').click()
+
+Post a comment as user jim.
+
+    >>> browser_member.open(urldoc1)
+    >>> browser_member.getControl(name='form.widgets.text').value = "Use the ZODB, Luke!"
+    >>> submit = browser_member.getControl(name='form.buttons.comment')
+    >>> submit.click()
+
+Check if there are no validation errors.
+
+    >>> 'Required input missing' in browser_member.contents
+    False
+    >>> 'Your comment awaits moderator approval' in browser_member.contents
+    True