Try to guess server's IP when there's more than one

The previous way of guessing the IP address of the server
for Capybara tests failed if we had more than one IP address.

This new way doesn't guarantee to pick the right IP, but it
works strictly better than the previous one.

config/initializers/selenium_docker.rb

@@ -13,7 +13,7 @@
 
 def setup_capybara_docker_driver_if_needed
   unless ENV['SELENIUM_URL'].nil? || ENV['SELENIUM_URL'].empty?
-    ip = `/sbin/ip route|awk '/scope/ { print $9 }'`.gsub("\n", "")
+    ip = `/sbin/ip route|awk '/scope/ { print $9 }'`.split("\n").last
 
     Capybara.javascript_driver = :docker_firefox
     Capybara.server_port = 55555