Merge 1734817, 1734955, r1734989, from trunk:

Merge 1734817, 1734955, r1734989, from trunk:

mod_include now sets DOCUMENT_ARGS.

* Like DOCUMENT_URI, this is for the SSI document, not for any
  subrequest called for the include directive.
* Like QUERY_STRING, this is just r->args (or empty string if there are
  none), unlike QUERY_STRING_UNESCAPED.

The name of the variable is taken from the Zeus SSI implementation.

Follow-up to r1734817: suexec passes through mod_include's DOCUMENT_ARGS

Follow-up to r1734817: Reorder, mention compatibility

Submitted by: trawick
Reviewed by: jim, ylavic

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1735963 13f79535-47bb-0310-9956-ffa450edef68