Merge branch 'ce-6517-extract-ee-specific-files-lines-for-spec-services-emails' into 'master'

Freeze strings in email service specs

See merge request gitlab-org/gitlab-ce!26485

spec/services/emails/create_service_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Emails::CreateService do

spec/services/emails/destroy_service_spec.rb

+# frozen_string_literal: true
+
 require 'spec_helper'
 
 describe Emails::DestroyService do