remove protection of the name `sidebar` from wiki

This should have been removed with #caad6495a5

app/models/wiki_page.rb

@@ -62,7 +62,6 @@ class WikiPage < ActiveRecord::Base
   validate :validate_non_circular_dependency
   validate :validate_same_project
 
-  after_initialize :check_and_mark_as_protected
   before_save :update_redirects
   before_destroy :remove_redirects
 
@@ -82,17 +81,8 @@ class WikiPage < ActiveRecord::Base
       .merge(Project.allowed_to(user, :view_wiki_pages))
   }
 
-  # Wiki pages that are protected by default
-  DEFAULT_PROTECTED_PAGES = %w(sidebar)
-
   after_destroy :delete_wiki_menu_item
 
-  def check_and_mark_as_protected
-    if new_record? && DEFAULT_PROTECTED_PAGES.include?(title.to_s.downcase)
-      self.protected = true
-    end
-  end
-
   def slug
     read_attribute(:slug).presence || title.try(:to_url)
   end

spec_legacy/unit/wiki_page_spec.rb

@@ -50,12 +50,6 @@ describe WikiPage, type: :model do
     assert @wiki.pages.include?(page)
   end
 
-  it 'should sidebar should be protected by default' do
-    page = @wiki.find_or_new_page('sidebar')
-    assert page.new_record?
-    assert page.protected?
-  end
-
   it 'should find or new page' do
     page = @wiki.find_or_new_page('CookBook documentation')
     assert_kind_of WikiPage, page