Compile newer libpcap for Linux release

[philrz]

I'm not sure if this is the best way to go about it, but with the changes in this PR I've created a Zeek artifact that uses a newer libpcap and successfully processes pcapng files whereas the prior artifact did not.

# old-zeek/zeek/zeek -C -r hello.pcapng local
fatal error: problem with trace file hello.pcapng (invalid interface capture length 524288, bigger than maximum of 262144)

# new-zeek/zeek/zeek -C -r hello.pcapng local
WARNING: No Site::local_nets have been defined.  It's usually a good idea to define your local networks.
phil@phil-linux:~$ ls -l *.log
-rw-rw-r-- 1 phil phil   276 Apr 27 00:17 capture_loss.log
-rw-rw-r-- 1 phil phil   617 Apr 27 00:17 conn.log
-rw-rw-r-- 1 phil phil   783 Apr 27 00:17 files.log
-rw-rw-r-- 1 phil phil   881 Apr 27 00:17 http.log
-rw-rw-r-- 1 phil phil 31170 Apr 27 00:17 loaded_scripts.log
-rw-rw-r-- 1 phil phil   254 Apr 27 00:17 packet_filter.log
-rw-rw-r-- 1 phil phil   706 Apr 27 00:17 stats.log

Closes #17