bro Including local_nets on the command line

gistfile1.txt

wpad:tmp2 liamrandall$ bro -r /Users/liamrandall/TrafficSamples/xmas2011.pcap local "Site::local_nets += {10.0.0.0/8, 192.168.0.0/16, 172.16.0.0/12}"
wpad:tmp2 liamrandall$ ls *.log
conn.log           ftp.log            known_hosts.log    loaded_scripts.log packet_filter.log  signatures.log     software.log
files.log          http.log           known_services.log notice.log         pe.log             smtp.log
wpad:tmp2 liamrandall$ bro -v
bro version 2.4-beta
wpad:tmp2 liamrandall$ less known_
known_: No such file or directory
wpad:tmp2 liamrandall$ cat known_hosts.log
#separator \x09
#set_separator	,
#empty_field	(empty)
#unset_field	-
#path	known_hosts
#open	2015-06-04-11-28-27
#fields	ts	host
#types	time	addr
1324817472.967189	192.168.1.3
1324817472.967189	192.168.1.10
1324817511.391073	172.19.79.2
1324817828.506717	172.19.79.6
#close	2015-06-04-11-28-27
wpad:tmp2 liamrandall$