client: change how we hndle busy-waiting for reboot and claim-host.

Previously, we would print an irritating empty newline if we could claim
the host right away. Fix this.

Signed-off-by: Olaf Kirch <okir@suse.de>
Introduce node-by-nickname and assorted set of functions

Signed-off-by: Olaf Kirch <okir@suse.de>
Introduce more testbus_node_* shell functions

Signed-off-by: Olaf Kirch <okir@suse.de>