Merge from trunk r1547845:

mod_cache_disk: Fix potential hangs on Windows when using mod_cache_disk.

PR: 55833
Submitted by: covener
Reviewed by: jim, trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1555721 13f79535-47bb-0310-9956-ffa450edef68