Make iptables-restore usable over a pipe

The attached patch flushes stdout between commands to make output
operations (-L etc) in iptables-restore usable over a pipe. stdio by
defaut buffers output if not connected to a terminal.

Henrik Nordstrom <henrik@henriknordstrom.net>
diff --git a/ip6tables-restore.c b/ip6tables-restore.c
index 6e41d51..9f6108a 100644
--- a/ip6tables-restore.c
+++ b/ip6tables-restore.c
@@ -436,6 +436,7 @@
 					 &newargv[2], &handle);
 
 			free_argv();
+			fflush(stdout);
 		}
 		if (!ret) {
 			fprintf(stderr, "%s: line %u failed\n",