Merge r467259, r467274 from trunk:

128 is enough for CPING/CPONG messages.

Add CPING/CPONG message size as defined as max inside Apache Tomcat using define.
Submitted by: mturk
Reviewed by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@615931 13f79535-47bb-0310-9956-ffa450edef68