Update the Travis configuration file to point to Android 25.
Update the Travis configuration file to point to Android 25.

gavinliu/turbolinks-android,gavinliu/turbolinks-android,timoschloesser/turbolinks-android,timoschloesser/turbolinks-android,turbolinks/turbolinks-android,timoschloesser/turbolinks-android,turbolinks/turbolinks-android,gavinliu/turbolinks-android,turbolinks/turbolinks-android,timoschloesser/turbolinks-android,gavinliu/turbolinks-android,turbolinks/turbolinks-android