Convert the worker MPM's fdqueue from a LIFO back into a FIFO. Since

Convert the worker MPM's fdqueue from a LIFO back into a FIFO. Since
elements in the queue represent accept()ed connections, we want them
to be processed in the order that they were received.  (I erroneously
converted it to a LIFO quite awhile ago in the hopes that it would
improve cache efficiency.)

Remember to perform a make clean in the worker directory after this patch,
since this patch changes the size of the fd_queue_t object (which is
allocated in worker.c).

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@94813 13f79535-47bb-0310-9956-ffa450edef68