Merge r170441, r170573, r170719 from trunk:

Merge r170441, r170573, r170719 from trunk:

* server/log.c (piped_log_spawn): Return the APR error code,
as expected by piped_log_maintenance (and fixing "Unknown
error" messages in error path there).
(ap_open_piped_log): Expect an APR error code.

* server/log.c (ap_open_piped_log): Remove errno handling.

* server/log.c (piped_log_spawn): Don't leak an fd for each
invocation.

Reviewed by: jorton, trawick, wrowe

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@227329 13f79535-47bb-0310-9956-ffa450edef68