fix segfault in example in nflog_get_payload()

This patch fixes the following segfault while executing the example
file in my laptop.

==5635== Process terminating with default action of signal 11 (SIGSEGV)
==5635==  Access not within mapped region at address 0x0
==5635==    at 0x403EEB7: nflog_get_payload (libnetfilter_log.c:437)
==5635==    by 0x8048D6B: print_pkt (nfulnl_test.c:17)
==5635==    by 0x403F5F7: __nflog_rcv_pkt (libnetfilter_log.c:132)
==5635==    by 0x418AD8F: __nfnl_handle_msg (libnfnetlink.c:1241)
==5635==    by 0x418AE0C: nfnl_handle_packet (libnfnetlink.c:1261)
==5635==    by 0x403FC0C: nflog_handle_packet (libnetfilter_log.c:218)
==5635==    by 0x8048C8F: main (nfulnl_test.c:110)

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

0 files changed, 0 insertions, 0 deletions