Broken master in spec/features/issues/user_uses_slash_commands_spec.rb

It seems that master is broken since https://gitlab.com/gitlab-org/gitlab-ce/commit/1350d80ca2f2633c8104460c4b9a60eb189a767b (https://gitlab.com/gitlab-org/gitlab-ce/-/jobs/65994871).

By looking at the screenshots, it seems the user is not signed-in: https://gitlab.com/gitlab-org/gitlab-ce/-/jobs/65994871/artifacts/file/tmp/capybara/screenshot_2018-05-02-08-53-32.686.png

Interestingly, the spec file is the first to run.