RFC 2616 says "All 1xx (informational), 204 (no content), and 304 (not

RFC 2616 says "All 1xx (informational), 204 (no content), and 304 (not
modified) responses MUST NOT include a message-body," so
Content-Length: is not needed in these cases (and Apache does indeed
not include it).  This causes PassBody() to call pass_straight() with
a NULL length argument, which waits until the connection is closed by
the server.  PassBody() should not call pass_*() at all for responses
that are known to be bodyless.

Submitted by:	Dagfinn Ilmari Mannsåker <ilmari@ping.uio.no>

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@1138 d4fa192b-c00b-0410-8231-f00ffab90ce4