ab: Fix a command-line processing bug; track bad headers in

err_response; support reading headers up to 2K.  (In the
original patch it was 8K instead of 2K; it isn't clear to me
that 8K is really needed or appropriate.)
Submitted by:	Ask Bjoern Hansen <ask@valueclick.com>
Reviewed by:	Jeff Trawick


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85251 13f79535-47bb-0310-9956-ffa450edef68