MINOR: http-rules: Support an optional status on deny rules for http reponses

It is now possible to specified the status code to return an http-response deny
rules. For instance :

    http-response deny deny_status 500
diff --git a/src/http_ana.c b/src/http_ana.c
index 628116d..574f6eb 100644
--- a/src/http_ana.c
+++ b/src/http_ana.c
@@ -3073,7 +3073,7 @@
 
 			case ACT_ACTION_DENY:
 				txn->flags |= TX_CLDENY;
-				txn->status = 502;
+				txn->status = http_err_codes[rule->arg.http.i];
 				rule_ret = HTTP_RULE_RES_DENY;
 				goto end;