generalize the existing (r589761) platform- and errno-specific

logic to suppress an error message if accept() fails after the
socket has been marked inactive

a message will still be logged, but at debug level instead of error

PR: 49058


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@933657 13f79535-47bb-0310-9956-ffa450edef68