backport this fix from 2.1-dev:

     Fix a long delay with CGI requests and keepalive connections on
     AIX.

Reviewed by:	stoddard, jerenkrantz


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/APACHE_2_0_BRANCH@102297 13f79535-47bb-0310-9956-ffa450edef68