Update user.pp to allow IPv6

[rudybroersma]

This change adds IPv6 addresses to the authorized_keys file of the backshots user. This is required, as OpenSSH 6.8 and up have changed the use of the configuration parameter "UseDNS" from Yes to No, which means that SSHd will no longer be doing DNS lookups.

Without this patch, a backup server that tries to connect using IPv6 to a server that has UseDNS set to 'no', the connection will fail.

[rudybroersma]

I am not fully happy with my proposed patch, as it will mean a change to this code when Puppet has resolved the bug I am referring to in the patch . Another solution might be to use:

$backup_server_ipv6 = inline_template("<% _erbout.concat(begin Resolv::DNS.new.getresource('${server}', Resolv::DNS::Resource::IN::AAAA).address.to_s rescue '' end) %>")

[tedivm]

Yeah I'd be worried about accepting code that is going to break later, or which will have to be updated in a way that isn't backwards compatible.

[rudybroersma]

Alright I'll await the output from the bugreport, and see what we can do to resolve the issue when there is more information from the bugreport. But how about the 'other solution' ? That does work, regardless of the bug(report)

[rudybroersma]

Alright, there is a conclusion to the bug report. The original report is here:

https://tickets.puppetlabs.com/browse/SERVER-1801

Puppet concludes its an issue in JRuby, that report is here:

jruby/jruby#4594

JRuby concludes its a setting in Java:

https://docs.oracle.com/javase/7/docs/api/java/net/doc-files/net-properties.html

So it seems my original patch is correct and the use of .last is correct.

[rudybroersma]

Can you take another look at this PR? My original patch is correct, what I believed to be a bug is apparantly expected and correct behaviour.

[tedivm]

I'll give it a review next week.