ip6-nd: fix coverity warning

Add a missing return statement in case there are no parameters supplied
to 'set ip6 nd proxy' CLI to avoid calling code with uninitialised
parameters.

Type: fix
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: Ie4fdb4df5d1af49471c421e5e7a6c2f885d2e8d2
diff --git a/src/vnet/ip6-nd/ip6_nd_proxy.c b/src/vnet/ip6-nd/ip6_nd_proxy.c
index ea7ca56..256b485 100644
--- a/src/vnet/ip6-nd/ip6_nd_proxy.c
+++ b/src/vnet/ip6-nd/ip6_nd_proxy.c
@@ -107,6 +107,10 @@
 	    return (unformat_parse_error (input));
 	}
     }
+  else
+    {
+      return error;
+    }
 
   ip6_nd_proxy_add_del (sw_if_index, &addr, is_del);