call logout on bz platform too to keep things straight

lib/casserver/server.rb

@@ -556,6 +556,8 @@ def self.init_database!
 
       @message[:message] += t.notice.click_to_continue if @continue_url
 
+      @log_out_of_services = true
+
       @lt = generate_login_ticket
 
       if @gateway && @service

lib/casserver/views/_login_form.erb

@@ -1,3 +1,14 @@
+<% if @log_out_of_services %>
+<!-- The purpose of this is to log out of all our dependent services, so a user
+     doesn't get trapped in a weird circle of logging out of Canvas, but still
+     being another user on BZ and thereby getting jerked around in a confusing
+     circle when she goes back to the home page.
+
+     Since it is a cross-domain, client side cookie, we had to implement this
+     using a helper method on the other side and an iframe on this side.
+-->
+  <iframe style="visibility: hidden; width: 1px; height: 1px;" src="//<%= @domain %>/users/clear_session_cookie"></iframe>
+<% end %>
 <form method="post" action="<%= @form_action || "login" %>" id="login-form"
       onsubmit="submitbutton = document.getElementById('login-submit'); submitbutton.value='<%= t.notice.please_wait %>'; submitbutton.disabled=true; return true;">
         <div><label id="username-label" for="username">
@@ -19,4 +30,3 @@
         <%= @infoline %>
       </div>
 </form>
-