Fix a couple of pool-related bugs that may or may not be causing actual

problems. This makes sure that all interactions with the
thread_pool_parent are mutexed, and makes ap_put_os_sock use the correct
pool in worker_thread().


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@84069 13f79535-47bb-0310-9956-ffa450edef68