Advertise netconf:base:1.0 capability

The JNC Netconf client library doesn't support 1.1, so we need to
advertise support for the older protocol.
Add netconf:base:1.0 capability to config_gen

The JNC Netconf client library doesn't support 1.1, so we need to
advertise support for the older protocol.
Merge pull request #220 from legoscia/enetconf-capabilities

Advertise netconf:base:1.0 capability