Fix new timing bug in a Capybara integration test.
Fix new timing bug in a Capybara integration test.

NoMethodError: undefined method `click' for nil:NilClass
test/integration/capybara_lurker_test.rb:92:in `test_show_observation'

Capybara now clicks on Login before the page is fully loaded.
So ensure that the Login link is loaded before clicking.

I noticed this bug only recently.  Not sure why it's happening: has test speeded up? page load slowed down?
In any event, it's fixed.

pellaea/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,JoeCohen/mushroom-observer,JoeCohen/mushroom-observer,JoeCohen/mushroom-observer,raysuelzer/mushroom-observer,JoeCohen/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,raysuelzer/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,raysuelzer/mushroom-observer,MushroomObserver/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,pellaea/mushroom-observer,JoeCohen/mushroom-observer,MushroomObserver/mushroom-observer,pellaea/mushroom-observer,raysuelzer/mushroom-observer,JoeCohen/mushroom-observer