kubernetes: Remove obsolete docker host disabling documentation

Commit b772ad7 removed the diversion of various Docker registry host
names to localhost from docker-images.setup, as tests now don't have an
internet connection. Drop the corresponding documentation of that.

Reviewed-by: Stef Walter <stefw@redhat.com>

examples/kubernetes/README.md

@@ -6,7 +6,4 @@ need to run the following to access services:
     $ sudo ip route add 172.30.0.0/16 via 10.111.112.101
 
 This image is preloaded with the docker images needed to run the cockpit
-integration tests. In order to avoid test flakes due to network issues, any
-further image downloads are blocked by redirecting common docker registry
-domains to 127.0.0.1 (localhost) in /etc/hosts. If you need to download new
-images for manual tests you will need to remove those entries from /etc/hosts.
+integration tests.