Set remove_default_searchdomains to false by default

It was not 'false', which made some tasks (e.g. using systemd-resolved
template) to effectively remove default search domains; caused DNS loop
after rebooting the node/restarting cluster, so localdns service didn't
run correctly.

roles/kubernetes/preinstall/defaults/main.yml

@@ -23,6 +23,9 @@ common_required_pkgs:
 # GCE docker repository
 disable_ipv6_dns: false
 
+# Remove default cluster search domains (``default.svc.{{ dns_domain }}, svc.{{ dns_domain }}``).
+remove_default_searchdomains: false
+
 kube_owner: kube
 kube_cert_group: kube-cert
 kube_config_dir: /etc/kubernetes