frestart: Look for ERROR instead of QUIT

The IRCd sends ERROR when we get disconnected, so this is more reliable.

src/wolfgame.py

@@ -581,36 +581,8 @@ def restart_program(cli, nick, chan, rest):
     except Exception:
         notify_error(cli, chan, errlog)
 
-    @hook("quit")
+    @hook("error")
     def restart_buffer(*s):
-        # *** BIG FLASHY RED WARNING GOES HERE ***
-        # THERE IS A POTENTIAL RACE CONDITION IN THIS CODE
-
-        # this is due to the fact that the socket's buffer is not empty
-        # when we reach the os.execl calls, so we kill the process before
-        # the buffer is done being sent. someone who knows better than me
-        # at sockets should probably try to fix this properly. for now, this
-        # is actually a working fix; we want to wait until the above quit
-        # call is processed (we see our own quit). I prefer false positives
-        # over false negatives, so I'd rather have this hook trigger on more
-        # quits than not enough. the race condition mentioned above happens
-        # if someone else quits while the bot is still sending data. I haven't
-        # actually tested this to see if it processes received data even if
-        # it's currently sending stuff, thus why it's a "potential" race
-        # condition anyway. I'm fairly sure we can, though, so this is a
-        # bug. however this is a rare bug and would cause annoyance only in
-        # some times, while the previous behaviour caused annoyance at all
-        # times, since the process was killed before all the buffering could
-        # be processed. should this happen, the bot was waiting for its own
-        # quit to restart anyway, so it's not restarting while nothing was
-        # supposed to happen. this isn't a critical bug (I hear you woffle,
-        # yes we should fix it better, but this is also less worse than it
-        # used to be, any upside is good to take; if we can't fix it in one
-        # go better to at least fix what we can), but a bug nonetheless, and
-        # should be fixed as soon as someone finds a proper fix. -Vgr
-
-        # TL;DR - data does not finish sending before we kill the process
-
         plog("RESTARTING")
 
         python = sys.executable