[NET]: Need to export secpath_dup to modules.

net/netsyms.c

@@ -322,6 +322,7 @@ EXPORT_SYMBOL(xfrm_replay_advance);
 EXPORT_SYMBOL(xfrm_check_selectors);
 EXPORT_SYMBOL(xfrm_check_output);
 EXPORT_SYMBOL(__secpath_destroy);
+EXPORT_SYMBOL(secpath_dup);
 EXPORT_SYMBOL(xfrm_get_acqseq);
 EXPORT_SYMBOL(xfrm_parse_spi);
 EXPORT_SYMBOL(xfrm4_rcv);