Fix: IPv4 options parse.

Thanks to Alexander for bug report.

Oct 31 11:26:07 servername kernel: [56560.220012] BUG: soft lockup - CPU#6 stuck for 22s! [ksoftirqd/6:38]
Oct 31 11:26:07 servername kernel: [56560.220012] Modules linked in: ipt_NETFLOW(O) ip6table_filter(F) ip6_tables(F) xt_IMQ(F) iptable_mangle(F) xt_CT(F) iptable_raw(F) xt_nat(F) xt_mark(F) iptable_nat(F) nf_nat_ipv4(F) nf_nat(F) nf_conntrack_ipv4(F) nf_defrag_ipv4(F)
+xt_state(F) xt_tcpudp(F) nf_conntrack(F) xt_hashlimit(F) xt_set(F) iptable_filter(F) ip_tables(F) x_tables(F) sch_sfq(F) cls_fw(F) cls_u32(F) sch_htb(F) imq(F) ip_set_hash_ip(F) ip_set_hash_net(F) ip_set(F) nfnetlink(F) bonding(F) radeon(F) kvm(F) ttm(F)
+drm_kms_helper(F) drm(F) gpio_ich(F) i5000_edac(F) igb(OF) edac_core(F) psmouse(F) lpc_ich(F) shpchp(F) microcode(F) i5k_amb(F) serio_raw(F) coretemp(F) joydev(F) dcdbas(F) mac_hid(F) lp(F) parport(F) usb_storage(F) hid_generic(F) usbhid(F) hid(F) mptsas(F)
+i2c_algo_bit(F) mptscsih(F) dca(F) mptbase(F) ptp(F) scsi_transport_sas(F) pps_core(F) bnx2(F) [last unloaded: ipt_NETFLOW]
Oct 31 11:26:07 servername kernel: [56560.220012] CPU: 6 PID: 38 Comm: ksoftirqd/6 Tainted: GF       W  O 3.10.17-custom-imq #2
Oct 31 11:26:07 servername kernel: [56560.220012] Hardware name: Dell Inc. PowerEdge 1950/0TT740, BIOS 2.6.1 04/20/2009
Oct 31 11:26:07 servername kernel: [56560.220012] task: ffff8801294a5dc0 ti: ffff8801294ae000 task.ti: ffff8801294ae000
Oct 31 11:26:07 servername kernel: [56560.220012] RIP: 0010:[<ffffffffa029f71e>]  [<ffffffffa029f71e>] netflow_target+0xcbe/0x1124 [ipt_NETFLOW]
Oct 31 11:26:07 servername kernel: [56560.220012] RSP: 0018:ffff8801294af930  EFLAGS: 00000202
Oct 31 11:26:07 servername kernel: [56560.220012] RAX: ffff88006d7b2376 RBX: 0000000000394d98 RCX: 0000000000000000
Oct 31 11:26:07 servername kernel: [56560.220012] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 000000000000006c
Oct 31 11:26:07 servername kernel: [56560.220012] RBP: ffff8801294afa30 R08: 000000000000000c R09: 0000000000000001
Oct 31 11:26:07 servername kernel: [56560.220012] R10: 0000000000000020 R11: 00000000c8fe9f4f R12: ffff8801294af938
Oct 31 11:26:07 servername kernel: [56560.220012] R13: ffff8801294af930 R14: 000000000e000000 R15: 00000000000000e0
Oct 31 11:26:07 servername kernel: [56560.220012] FS:  0000000000000000(0000) GS:ffff88012fd80000(0000) knlGS:0000000000000000
Oct 31 11:26:07 servername kernel: [56560.220012] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Oct 31 11:26:07 servername kernel: [56560.220012] CR2: 00007fb04e59fc60 CR3: 00000001271dd000 CR4: 00000000000007e0
Oct 31 11:26:07 servername kernel: [56560.220012] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
Oct 31 11:26:07 servername kernel: [56560.220012] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Oct 31 11:26:07 servername kernel: [56560.220012] Stack:
Oct 31 11:26:07 servername kernel: [56560.220012]  ffff880100000000 ffff880125ba0000 ffff88006c844dc0 ffff88010000000c
Oct 31 11:26:07 servername kernel: [56560.220012]  0000000000000000 00000000300001a2 00000000000005ae ffff880127de1e10
Oct 31 11:26:07 servername kernel: [56560.220012]  00000000294afa08 ffff8801294af940 0000000000000034 ffff8801294af9b8
Oct 31 11:26:07 servername kernel: [56560.220012] Call Trace:
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff816aa135>] ? _raw_read_unlock_bh+0x15/0x20
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffffa00cb6de>] ? ip_set_test+0x8e/0x120 [ip_set]
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffffa01df156>] ipt_do_table+0x2c6/0x5e5 [ip_tables]
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffffa01d60d3>] iptable_filter_hook+0x33/0x64 [iptable_filter]
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815d3766>] nf_iterate+0x86/0xb0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815db920>] ? ip_frag_mem+0x40/0x40
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815d3804>] nf_hook_slow+0x74/0x150
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815db920>] ? ip_frag_mem+0x40/0x40
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815dbd60>] ip_forward+0x3c0/0x3e0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815d9b38>] ip_rcv_finish+0x78/0x320
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815d474b>] nf_reinject+0xdb/0x170
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815d9ac0>] ? inet_add_protocol+0x50/0x50
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffffa00c61d9>] imq_dev_xmit+0x99/0xd0 [imq]
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815a8524>] dev_hard_start_xmit+0x314/0x510
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815c5eb0>] sch_direct_xmit+0xf0/0x1c0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815c6009>] __qdisc_run+0x89/0x150
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff815a4ff9>] net_tx_action+0xe9/0x1a0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff8104ba67>] __do_softirq+0xe7/0x230
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff8104bbd8>] run_ksoftirqd+0x28/0x40
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff81070d2f>] smpboot_thread_fn+0x10f/0x1a0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff816a90b9>] ? schedule+0x29/0x70
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff81070c20>] ? lg_global_unlock+0x60/0x60
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff81069350>] kthread+0xc0/0xd0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff81069290>] ? kthread_create_on_node+0x120/0x120
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff816b275c>] ret_from_fork+0x7c/0xb0
Oct 31 11:26:07 servername kernel: [56560.220012]  [<ffffffff81069290>] ? kthread_create_on_node+0x120/0x120
Oct 31 11:26:07 servername kernel: [56560.220012] Code: 09 da 40 84 ff 75 19 89 95 2c ff ff ff 48 c7 c3 20 40 01 00 48 8b a5 48 ff ff ff e9 97 f4 ff ff 41 39 f0 76 e2 40 80 ff 01 74 ac <48> 63 ce 0f b6 0c 08 8d 74 0e ff eb 9f c7 85 2c ff ff ff 00 00