spec_helper_acceptance: add abbility to enable Ipv6 in beaker hosts

Enabled by default
Also see: voxpupuli/modulesync_config#694

Author: b4ldr

lib/voxpupuli/acceptance/spec_helper_acceptance.rb

@@ -51,6 +51,7 @@ def configure_beaker(modules: :metadata, &block)
           copy_hiera_data_to(hosts, hiera_data_dir)
         end
       end
+      on(hosts, 'echo 0 > /proc/sys/net/ipv6/conf/all/disable_ipv6') if enable_ipv6
 
       hosts.each do |host|
         if block