VTY: Remove some more SUBSCR_NODE related code

SUBSCR_NODE has been eliminated recently, so this is dead code.
diff --git a/openbsc/src/common_vty.c b/openbsc/src/common_vty.c
index eb0d29e..0c724d6 100644
--- a/openbsc/src/common_vty.c
+++ b/openbsc/src/common_vty.c
@@ -66,11 +66,6 @@
 			vty->index = ts->trx;
 		}
 		break;
-	case SUBSCR_NODE:
-		vty->node = VIEW_NODE;
-		subscr_put(vty->index);
-		vty->index = NULL;
-		break;
 	default:
 		vty->node = CONFIG_NODE;
 	}