Transient failure in rspec 2 20

As seen in https://gitlab.com/gitlab-org/gitlab-ee/builds/17073564

 1) Issue Boards add issue modal shows weight filter
     Failure/Error: wait_for_vue_resource

     NameError:
       undefined local variable or method `wait_for_vue_resource' for #<RSpec::ExampleGroups::IssueBoardsAddIssueModal:0x0000002280e9c8>
       Did you mean?  wait_for_requests
     # ./spec/features/boards/add_issues_modal_spec.rb:39:in `block (2 levels) in <top (required)>'
     # ./spec/spec_helper.rb:81:in `block (2 levels) in <top (required)>'