Fix sign in form when just Kerberos is enabled

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

@@ -4,7 +4,7 @@
     = render 'devise/shared/signin_box'
 
   -# Omniauth fits between signin/ldap signin and signup and does not have a surrounding box
-  - if Gitlab.config.omniauth.enabled && devise_mapping.omniauthable?
+  - if Gitlab.config.omniauth.enabled && devise_mapping.omniauthable? && button_based_providers.any?
     .clearfix.prepend-top-20
       = render 'devise/shared/omniauth_box'
 

app/views/devise/shared/_signin_box.html.haml

@@ -8,9 +8,10 @@
   .login-body
     - if form_based_providers.any?
       %ul.nav.nav-tabs
-        - @ldap_servers.each_with_index do |server, i|
-          %li{class: (:active if i.zero?)}
-            = link_to server['label'], "#tab-#{server['provider_name']}", 'data-toggle' => 'tab'
+        - if ldap_enabled?
+          - @ldap_servers.each_with_index do |server, i|
+            %li{class: (:active if i.zero?)}
+              = link_to server['label'], "#tab-#{server['provider_name']}", 'data-toggle' => 'tab'
         - if kerberos_enabled?
           %li{class: (:active unless ldap_enabled?)}
             = link_to "Kerberos", "#tab-kerberos", 'data-toggle' => 'tab'
@@ -18,9 +19,10 @@
           %li
             = link_to 'Standard', '#tab-signin', 'data-toggle' => 'tab'
       .tab-content
-        - @ldap_servers.each_with_index do |server, i|
-          %div.tab-pane{id: "tab-#{server['provider_name']}", class: (:active if i.zero?)}
-            = render 'devise/sessions/new_ldap', server: server
+        - if ldap_enabled?
+          - @ldap_servers.each_with_index do |server, i|
+            %div.tab-pane{id: "tab-#{server['provider_name']}", class: (:active if i.zero?)}
+              = render 'devise/sessions/new_ldap', server: server
         - if kerberos_enabled?
           %div#tab-kerberos.tab-pane{class: (:active unless ldap_enabled?)}
             = render 'devise/sessions/new_kerberos', provider: :kerberos