Submitted by: Chuck Murcko

Fix for Netscape 2.x keepalive problems. This also removes the HTTP header
flush which was causing TCP slow start/delayed ACK/delayed segment on keepalives,
eating up ~400 ms (1) additional per keepalive connect, plus latency. This
is in essence the previously submitted fix, using BrowserMatch instead of a
dedicated function.

Reference:
    Heidemann et al. -
      Performance Interactions Between P-HTTP and TCP Implementations
      <http://www.isi.edu/lsam/publications/phttp_tcp_interactions/>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@76795 13f79535-47bb-0310-9956-ffa450edef68