Revert "irc-announce: fix cat2 on live systems"

This reverts commit 6187206a02.

Lol, no.  Yes, /dev/stderr isn't POSIX (only fd 2 is and gawk has that
path hardcoded to the fd and thus it works), but the error is somewhere
else and "fixing" it like this doesn't help anyone.

krebs/5pkgs/irc-announce/default.nix

@@ -24,7 +24,7 @@ pkgs.writeDashBin "irc-announce" ''
   # echo2 and cat2 are used output to both, stdout and stderr
   # This is used to see what we send to the irc server. (debug output)
   echo2() { echo "$*"; echo "$*" >&2; }
-  cat2() { awk '{print;print > "/dev/stderr"}'; }
+  cat2() { tee /dev/stderr; }
 
   # privmsg_cat transforms stdin to a privmsg
   privmsg_cat() { awk '{ print "PRIVMSG "ENVIRON["IRC_CHANNEL"]" :"$0 }'; }