[CRIU] [PATCH 0/6] Unify external resources in CLI

[Pavel Emelyanov]

We have several resources that are told to criu to be "external"
and thus are to be dumped and/or restored individually. For each
we have an option in CLI and a field in rpc message.

Let's unify all this stuff under the --external option we have.

This set does so for --veth-pair and --ext-unix-sk ones. Next to
go would be the --ext-mount-map.

-- Pavel