Enhance NETCONF userfeatures test to not utilize odl-netconf-connector-ssh

Since Beryllium, we have suggested that users use the odl-netconf-

topology feature instead of odl-netconf-connector-ssh, since NETCONF has moved towards spawning connectors via the network-topology model. The NETCONF userfeatures tests currently rely on the controller loopback ("controller-config") which is provided by installing odl-netconf-connector-ssh. Since we are moving away from odl-netconf-connector-ssh feature, we should modify tests to not install the odl-netconf-connector-ssh feature, and find a new way to determine whether NETCONF is "up".