Backport:

mod_cache_disk: Make sure we check return codes on all writes and attempts
to close, and clean up after ourselves in these cases. PR43589.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1204602 13f79535-47bb-0310-9956-ffa450edef68