Moved handling of wev->delayed to the connection event handler. With post_action or subrequests, it is possible that the timer set for wev->delayed will expire while the active subrequest write event handler is not ready to handle this. This results in request hangs as observed with limit_rate / sendfile_max_chunk and post_action (ticket #776) or subrequests (ticket #1228). Moving the handling to the connection event handler fixes the hangs observed, and also slightly simplifies the code.