Fix mod_rewrite hang when APR uses SysV Semaphores. Before we were

silently failing when locking/unlocking the mutex, since httpd
child processes didn't have permissions to access the root-created
semaphore.

PR: 8143


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94969 13f79535-47bb-0310-9956-ffa450edef68