Bump version to 1.4.1-rc1

Actually its not a bump but a decrease, the autoconf patches
apparently sneaked it a version bump to 1.4.1 already.
diff --git a/configure.ac b/configure.ac
index 6a1cae0..48a8587 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,5 +1,5 @@
 
-AC_INIT([iptables], [1.4.1])
+AC_INIT([iptables], [1.4.1-rc1])
 AC_CONFIG_HEADERS([config.h])
 AC_PROG_INSTALL
 AM_INIT_AUTOMAKE