copy address of proc_ns_ops into ns_common

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

kernel/pid.c

@@ -80,6 +80,9 @@ struct pid_namespace init_pid_ns = {
 	.child_reaper = &init_task,
 	.user_ns = &init_user_ns,
 	.ns.inum = PROC_PID_INIT_INO,
+#ifdef CONFIG_PID_NS
+	.ns.ops = &pidns_operations,
+#endif
 };
 EXPORT_SYMBOL_GPL(init_pid_ns);