Use DELETE when signing out from registrar area

#599

config/locales/en.yml

@@ -816,7 +816,6 @@ en:
   notes: Notes
   active_price_for_this_operation_is: 'Active price for this operation is %{price}'
   active_price_missing_for_this_operation: 'Active price missing for this operation!'
-  log_out_: 'Log out'
   valid_to_from: 'Valid to from'
   valid_to_until: 'Valid to until'
   registrant_ident: 'Registrant ident'

config/locales/registrar/base.en.yml

@@ -0,0 +1,5 @@
+en:
+  registrar:
+    base:
+      current_user:
+        sign_out: Log out

config/routes.rb

@@ -44,7 +44,7 @@ Rails.application.routes.draw do
       post 'id' => 'sessions#id'
       post 'mid' => 'sessions#mid'
       get 'switch_user/:id' => 'sessions#switch_user'
-      get 'logout' => '/devise/sessions#destroy'
+      delete 'logout', to: '/devise/sessions#destroy', as: :destroy_user_session
     end
 
     get 'current_user/switch/:new_user_id', to: 'current_user#switch', as: :switch_current_user