Fix rubocop offenses. It's not checked before when

it's inside lib/tasks/*

.rubocop.yml

@@ -19,6 +19,10 @@ AllCops:
     - 'builds/**/*'
   CacheRootDirectory: tmp
 
+# TODO: Remove me after updating gitlab-style
+Style/TrailingUnderscoreVariable:
+  Enabled: false
+
 # Gitlab ###################################################################
 
 Gitlab/ModuleWithInstanceVariables:

lib/gitlab/task_helpers.rb

 require 'rainbow/ext/string'
 require 'gitlab/utils/strong_memoize'
 
+# rubocop:disable Rails/Output
 module Gitlab
   TaskFailedError = Class.new(StandardError)
   TaskAbortedByUserError = Class.new(StandardError)
@@ -96,12 +97,10 @@ module Gitlab
     end
 
     def gid_for(group_name)
-      begin
       Etc.getgrnam(group_name).gid
     rescue ArgumentError # no group
       "group #{group_name} doesn't exist"
     end
-    end
 
     def gitlab_user
       Gitlab.config.gitlab.user