Merge r1783842 from trunk:

mod_cache: Fix a regression in 2.4.25 for the forward proxy case by
computing and using the same entity key according to when the cache
checks, loads and saves the request.  PR 60577.

Submitted by: ylavic


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1788511 13f79535-47bb-0310-9956-ffa450edef68