tools: Introduce virshNodedevCapabilityNameCompleter

This is a very simple completer for completing --cap argument of
nodedev-list command.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
Reviewed-by: Erik Skultety <eskultet@redhat.com>

tools/virsh-nodedev.c

@@ -375,6 +375,7 @@ static const vshCmdOptDef opts_node_list_devices[] = {
     },
     {.name = "cap",
      .type = VSH_OT_STRING,
+     .completer = virshNodedevCapabilityNameCompleter,
      .help = N_("capability names, separated by comma")
     },
     {.name = NULL}