Merge 1621373 from trunk:

mod_slotmem: Increase log level for some originally debug messages.

Submitted by: jim
Reviewed by: jim, ylavic, rjung
Backported by: jailletc36

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1632437 13f79535-47bb-0310-9956-ffa450edef68