Transient failures `uninitialized constant EE::LdapHelpers`

Examples:
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bundler: failed to load command: rspec (/builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/bin/rspec)
NameError: uninitialized constant EE::LdapHelpers
  /builds/gitlab-org/gitlab-ee/spec/support/ldap_helpers.rb:2:in `<module:LdapHelpers>'
  /builds/gitlab-org/gitlab-ee/spec/support/ldap_helpers.rb:1:in `<top (required)>'
  /builds/gitlab-org/gitlab-ee/spec/spec_helper.rb:19:in `block in <top (required)>'
  /builds/gitlab-org/gitlab-ee/spec/spec_helper.rb:19:in `each'
  /builds/gitlab-org/gitlab-ee/spec/spec_helper.rb:19:in `<top (required)>'
  /builds/gitlab-org/gitlab-ee/spec/config/mail_room_spec.rb:1:in `require'
  /builds/gitlab-org/gitlab-ee/spec/config/mail_room_spec.rb:1:in `<top (required)>'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/configuration.rb:1435:in `load'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/configuration.rb:1435:in `block in load_spec_files'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/configuration.rb:1433:in `each'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/configuration.rb:1433:in `load_spec_files'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/runner.rb:100:in `setup'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/runner.rb:86:in `run'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/runner.rb:71:in `run'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/lib/rspec/core/runner.rb:45:in `invoke'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/gems/rspec-core-3.5.0/exe/rspec:4:in `<top (required)>'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/bin/rspec:22:in `load'
  /builds/gitlab-org/gitlab-ee/vendor/ruby/2.3.0/bin/rspec:22:in `<top (required)>'