We were submitting the form without checking the AJAX request to attach
the image had finished, so sometimes two requests were executed at the
same time. Sometimes this made InvisibleCaptcha to go crazy and report
the form was submitted too quickly.
Checking the first AJAX request has finished before submitting the form
solves the problem.
We were checking `expect_document_has_title(0, "My Title")`, which was
already true before the AJAX request generated by `attach_file` had
finished.
That meant the AJAX request sometimes was handled after this test had
finished, affecting the following test and causing it to fail because
its cookie was overwritten and so `current_user` was set to `nil`.
In the test checking the filename is present, a similar scenario was
taking place: we were updating the `.file-name` element in the `change`
event of `fileupload` (using `App.Documentable.setFilename`); that is,
when the AJAX request started. And so the test passed before the request
was finished, causing the same issue.
