Merge r1201571 from trunk:

PR52175: RewriteBase is what applies to relative substitutions, not
the stripping of the per-directory prefix.


Reviewed by: covener


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1201572 13f79535-47bb-0310-9956-ffa450edef68