rst: Ignore existed ifaddr during restore

After patch diff-ve-net-permanent-loopback-in_dev-20100205-2 (Bug #465470)
kernel would assign ip-address to loopback during registering. But rst code
code still consider this as error.

Bug https://bugzilla.sw.ru/show_bug.cgi?id=466541

Signed-off-by: Vitaliy Gusev <vgusev@openvz.org>

---
diff -up linux-2.6.9-051_9/kernel/cpt/rst_net.c~cpt linux-2.6.9-051_9/kernel/cpt/rst_net.c
--- linux-2.6.9-051_9/kernel/cpt/rst_net.c~cpt	2010-02-15 15:48:45.000000000 +0300
+++ linux-2.6.9-051_9/kernel/cpt/rst_net.c	2010-02-15 17:06:26.000000000 +0300
@@ -76,16 +76,18 @@ int rst_restore_ifaddr(struct cpt_contex
 				in_dev_hold(in_dev);
 				ifa->ifa_dev   = in_dev;
 				err = inet_insert_ifa(ifa);
-				if (err)
+				if (err && err != -EEXIST) {
+					rtnl_unlock();
 					eprintk_ctx("add ifaddr err %d for %d %s\n", err, di.cpt_index, di.cpt_label);
+					return err;
+				}
 			}
 		} else {
+			rtnl_unlock();
 			eprintk_ctx("unknown ifaddr 2 for %d\n", di.cpt_index);
-			err = -EINVAL;
+			return -EINVAL;
 		}
 		rtnl_unlock();
-		if (err)
-			return err;
 		sec += di.cpt_next;
 	}
 	return 0;

