vty: fix subscr ref count leak in 'subscriber name' cmd

Change-Id: I3d19518c94a7f302bf108f2ad945983cdc8db0b1
diff --git a/openbsc/src/libmsc/vty_interface_layer3.c b/openbsc/src/libmsc/vty_interface_layer3.c
index ddec2e3..cd5dfb7 100644
--- a/openbsc/src/libmsc/vty_interface_layer3.c
+++ b/openbsc/src/libmsc/vty_interface_layer3.c
@@ -586,6 +586,7 @@
 		vty_out(vty,
 			"%% NAME is too long, max. %zu characters are allowed%s",
 			sizeof(subscr->name)-1, VTY_NEWLINE);
+		subscr_put(subscr);
 		return CMD_WARNING;
 	}