Ensure consistent passwords during testing

[pablobm]

I noticed that in the latest commit (as of these lines), a change was introduced as follows:

-      fill_in "password", :with => "test"
+      fill_in "password", :with => "s3cr3t"

Upstream at OSM, this was introduced at openstreetmap#6431, as a means to work around a strange behaviour in Selenium. If changed in one place, it probably should change in all places to ensure consistency.

I quickly checked and this seems to help me when running tests locally:

staging:
2659 runs, 1106716 assertions, 104 failures, 54 errors, 0 skips

after these changes:
2659 runs, 1107275 assertions, 30 failures, 7 errors, 0 skips

[erictheise]

Thanks for this. I feel like we've done this in the past but in any case it's the right thing to do.