Merge r820760, r919323, r937858, r938265 from trunk:

Reviewed By: sf, trawick, covener

    core: Treat timeout reading request as 408 error, not 400.
    Log 408 errors in access log as was done in Apache 1.3.x.

    PR: 39785
    Submitted by: Nobutaka Mantani, Stefan Fritsch
    Reviewed and added to by: Dan Poirier


    * Only log a 408 if it is no keepalive timeout.

    PR: 39785
    Submitted by: Mark Montague <markmont umich.edu>, rpluem
    Reviewed by: rpluem


    PR49167, unexpected 413 and double-errordoc during a timeout reading a 
    chunk-size.



    Use the more specific 408 (timed out) instead of a generic 400 during a timeout 
    reading a chunk-length.




git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@1100200 13f79535-47bb-0310-9956-ffa450edef68