gb/vty: Fix the VTY node string for L_NS_NODE

Use 'config-ns' instead of plain 'ns' and append a blank after the
'#' to make the vty python test script work.

Sponsored-by: On-Waves ehf
diff --git a/src/gb/gprs_ns_vty.c b/src/gb/gprs_ns_vty.c
index 29f3159..4fa60ad 100644
--- a/src/gb/gprs_ns_vty.c
+++ b/src/gb/gprs_ns_vty.c
@@ -71,7 +71,7 @@
 
 static struct cmd_node ns_node = {
 	L_NS_NODE,
-	"%s(ns)#",
+	"%s(config-ns)# ",
 	1,
 };