If MaxMemFree is set, set SSL_MODE_RELEASE_BUFFERS in mod_ssl.

Always set SSL_MODE_RELEASE_BUFFERS in ab.

PR: 51618
Submitted by: Cristian Rodríguez <crrodriguez opensuse org>, Stefan Fritsch


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1178079 13f79535-47bb-0310-9956-ffa450edef68