Merge r611483, r639005, r639010 from trunk:

Support chroot on unix-family platforms
PR 43596 (Dimitar Pashev)


Document new ChrootDir directive (r611483)


mmn bump for chroot (r611483)

Submitted by: niq
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@696758 13f79535-47bb-0310-9956-ffa450edef68