Don't add a trailing dash to URL if missing path.

Adding a dash if missing the path component does not make sense.

Related bug:	#1584

bin/varnishncsa/varnishncsa.c

@@ -300,7 +300,7 @@ format_requestline(const struct format *format)
 		AZ(vsb_fcat(CTX.vsb, &CTX.frag[F_host], NULL));
 	} else
 		AZ(VSB_cat(CTX.vsb, "http://localhost"));
-	AZ(vsb_fcat(CTX.vsb, &CTX.frag[F_U], "-"));
+	AZ(vsb_fcat(CTX.vsb, &CTX.frag[F_U], NULL));
 	AZ(vsb_fcat(CTX.vsb, &CTX.frag[F_q], ""));
 	AZ(VSB_putc(CTX.vsb, ' '));
 	AZ(vsb_fcat(CTX.vsb, &CTX.frag[F_H], "HTTP/1.0"));