The socket may remain in the TIME_WAIT state for some time after the
server shuts down, which prevents another instance of the server from
listening on the same port. This change allows the server to reuse the
address even when it's still waiting.
Fixes an intermittent devserver problem with directory urls
containing index.html (i.e. clean urls). It tries to send the
index.html file twice, resulting in a scrambled web page complete
with HTTP headers in the output, and sometimes Broken Pipe errors.
