Merge r1646724, r1650309 from trunk:

tweak SCRIPT_FILENAME passed to fastcgi backends when a balancer is used.



save some bytes per Christophe's review.




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1651658 13f79535-47bb-0310-9956-ffa450edef68