beresp.backend.name (STRING)
	VCL name of backend fetched from.
	This name may have the form "somedirector[29]" if backends
	are declared directly in directors.

beresp.backend.ip (IP)
	IP number of remote end of connection.

beresp.backend.port (INT)
	TCP port number of remote end of connection.

Fixes:	#481


git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@5371 d4fa192b-c00b-0410-8231-f00ffab90ce4