Use consistent zeek_init priority for Log::create_stream calls

Typically in base scripts, Log::create_stream() is called in zeek_init()
handler with &priority=5 such that it will have already been created
in the default zeek_init() &priority=0.

scripts/policy/protocols/conn/known-hosts.zeek

@@ -145,7 +145,7 @@ event Known::host_found(info: HostsInfo)
 	event known_host_add(info);
 	}
 
-event zeek_init()
+event zeek_init() &priority=5
 	{
 	Log::create_stream(Known::HOSTS_LOG, [$columns=HostsInfo, $ev=log_known_hosts, $path="known_hosts"]);
 	}