Syncronize with trunk version.

This includes a couple of backports / fixes: r826805, r826822,
r829162, r829355, r829431. The default algorithm is now md5
on all platforms.
All patches by sf; backport reviewed by fuankg, wrowe, trawick.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1094184 13f79535-47bb-0310-9956-ffa450edef68