[squid-users] restart redirectors only patch

This is a small patch to squid-2.4/src/main.c which replaces
"-k debug" option (I don't need to switch to debug mode while squid is
running) with "-k redirect" which is restarting all redirectors only.
kill -USR2 `cat squid.pid` can be used also. I tested this on FreeBSD
only.
This is useful for squidGuard, which needs for full reconfiguring to run
squid -k reconfugure (kill -HUP `cat squid.pid`), but if you need to do
this very often it's not good for squid:)

Thanks,
Val