[fix] Hide empty disclaimer message on register page

Author: sman591

app/views/devise/registrations/new.html.haml

@@ -4,9 +4,9 @@
     Register for
     %span.emphasized= HackathonConfig['name']
 
-  - if HackathonConfig['registration_is_open'] || HackathonConfig['disclaimer_message'].present?
+  - if !HackathonConfig['registration_is_open'] || HackathonConfig['disclaimer_message'].present?
     #disclaimer
-      - unless HackathonConfig['registration_is_open']
+      - if !HackathonConfig['registration_is_open']
         .center
           %strong Registration is now closed. Thanks to everyone who applied!
         %br