REORG: include: move http_rules.h to haproxy/http_rules.h

There was no include file. This one still includes types/proxy.h.
diff --git a/src/vars.c b/src/vars.c
index de55f14..8cc4c48 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -3,12 +3,12 @@
 #include <haproxy/api.h>
 #include <common/cfgparse.h>
 #include <haproxy/http.h>
+#include <haproxy/http_rules.h>
 #include <haproxy/list.h>
 
 #include <types/vars.h>
 
 #include <haproxy/arg.h>
-#include <proto/http_rules.h>
 #include <proto/http_ana.h>
 #include <proto/sample.h>
 #include <proto/stream.h>