Remove the generation of flush bucket in mod_logio, now that

the nonblocking ap_core_output_filter knows how to defer the
call to the logio hook until the last bucket is actually
written to the network.
(backport from async-dev branch to 2.3 trunk)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@327888 13f79535-47bb-0310-9956-ffa450edef68