Don't globber scoreboard request info if read_request_line() fails with

a timeout. In that case there's not yet any new useful request info
available.
Noticed via server-status for prefork showing request "NULL" after
keep-alive connections timed out.

PR: 59333.
Backports: 1742792
Submitted by: rjung
Reviewed by: ylavic, wrowe


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1743516 13f79535-47bb-0310-9956-ffa450edef68