libxtables: consolidate init calls into one function

Introduce xtables_init_all() which hides three calls xtables_init(),
xtables_set_nfproto(), and xtables_set_params(). Make
ip[6]tables-restore, ip[6]tables-save and ip[6]tables-standalone use
it.

I moved xtables_set_params around for readability reasons.

Signed-off-by: Jamal Hadi Salim <hadi@cyberus.ca>
diff --git a/iptables-save.c b/iptables-save.c
index 396406f..312673a 100644
--- a/iptables-save.c
+++ b/iptables-save.c
@@ -140,9 +140,14 @@
 	program_version = IPTABLES_VERSION;
 
 	xtables_program_name = program_name;
-	xtables_init();
-	xtables_set_nfproto(NFPROTO_IPV4);
 	iptables_globals.program_name = "iptables-save";
+	c = xtables_init_all(&iptables_globals, NFPROTO_IPV4);
+	if (c < 0) {
+		fprintf(stderr, "%s/%s Failed to initialize xtables\n",
+				iptables_globals.program_name,
+				iptables_globals.program_version);
+		exit(1);
+	}
 #ifdef NO_SHARED_LIBS
 	init_extensions();
 #endif