do not delay if random_seed is undefined

Not sure if this matches your original intent or not, but I eliminated the sleep delay entirely if we're not using the -r option.  In my case, the individual logs in the logfile are from different hosts, and when the current line is backwards in time from the previous line (because it came from a host with a different local time), it introduces a random 0-3 second delay even if we're not using the -r flag.  This patch should let the script meet both of our needs, though (I hope).