REGTEST: the cache regtest requires haproxy 1.9

The chunks and the max-object-size features require version 1.9.
diff --git a/reg-tests/cache/h00000.vtc b/reg-tests/cache/h00000.vtc
index 5195816..100c860 100644
--- a/reg-tests/cache/h00000.vtc
+++ b/reg-tests/cache/h00000.vtc
@@ -1,6 +1,6 @@
 varnishtest "Basic cache test"
 
-#REQUIRE_VERSION=1.8
+#REQUIRE_VERSION=1.9
 
 feature ignore_unknown_macro