Fixed EmptyPass error message

mediawiki_api Ruby gem needs user password, but it is only set if the
scenario has @login Cucumber tag.

The entire error message: EmptyPass (MediawikiApi::LoginError)

For the entire stack trace see

1:
https://integration.wikimedia.org/ci/view/BrowserTests/job/browsertests-
Core-en.wikipedia.beta.wmflabs.org-linux-firefox-sauce/14/consoleFull

Change-Id: Ib5c297d9bfc1ca953d3aec27208fb99143fec011
Merge "Fixed EmptyPass error message"