Merge r562510 from trunk:

  *) mod_proxy: Improve network performance by setting APR_TCP_NODELAY
     (disable Nagle algorithm) on sockets if implemented.
     PR 42871 [Christian BOITEL <christian_boitel yahoo.fr>, Jim Jagielski]


Submitted by: Christian BOITEL <christian_boitel yahoo.fr>, jim
Reviewed by: rpluem, jim, fielding


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@572419 13f79535-47bb-0310-9956-ffa450edef68