Merge r1551714 from trunk:

Avoid sending back uninitialized memory, use 'ftpmessage' in order to have something meaningful instead.

Save 8k of stack by the same time.
Submitted by: jailletc36
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1555554 13f79535-47bb-0310-9956-ffa450edef68