Merge r1463052 from trunk:

use ap_log_error's facility to print the apr error string instead of
calling apr_strerror() explicitly

Submitted by: sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1470522 13f79535-47bb-0310-9956-ffa450edef68