Fix UnneededRequireStatement cop

.rubocop_todo.yml

@@ -91,14 +91,6 @@ Lint/ReturnInVoidContext:
   Exclude:
     - 'app/models/project.rb'
 
-# Offense count: 3
-# Cop supports --auto-correct.
-Lint/UnneededRequireStatement:
-  Exclude:
-    - 'db/post_migrate/20161221153951_rename_reserved_project_names.rb'
-    - 'db/post_migrate/20170313133418_rename_more_reserved_project_names.rb'
-    - 'lib/declarative_policy.rb'
-
 # Offense count: 9
 Lint/UriEscapeUnescape:
   Exclude:

db/post_migrate/20161221153951_rename_reserved_project_names.rb

-require 'thread'
-
 class RenameReservedProjectNames < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
   include Gitlab::ShellAdapter

db/post_migrate/20170313133418_rename_more_reserved_project_names.rb

-require 'thread'
-
 class RenameMoreReservedProjectNames < ActiveRecord::Migration
   include Gitlab::Database::MigrationHelpers
   include Gitlab::ShellAdapter

lib/declarative_policy.rb

@@ -10,8 +10,6 @@ require_dependency 'declarative_policy/step'
 
 require_dependency 'declarative_policy/base'
 
-require 'thread'
-
 module DeclarativePolicy
   CLASS_CACHE_MUTEX = Mutex.new
   CLASS_CACHE_IVAR = :@__DeclarativePolicy_CLASS_CACHE