CLEANUP: acl: don't reference the generic pattern deletion function anymore

A few ACL keyword used to reference pat_delete_gen() as the deletion
function but this is not needed since it's the default one now. Let's
just remove this reference.
diff --git a/src/http_acl.c b/src/http_acl.c
index d31592e..bf29fc3 100644
--- a/src/http_acl.c
+++ b/src/http_acl.c
@@ -121,8 +121,8 @@
 	 * and match method are related to the corresponding fetch methods. This
 	 * is very particular ACL declaration mode.
 	 */
-	{ "http_auth_group", NULL,       PAT_MATCH_STR, NULL,  pat_idx_list_str, pat_delete_gen, NULL, pat_match_auth },
-	{ "method",          NULL,       PAT_MATCH_STR, pat_parse_meth, pat_idx_list_str, pat_delete_gen, NULL, pat_match_meth },
+	{ "http_auth_group", NULL,       PAT_MATCH_STR, NULL,  pat_idx_list_str, NULL, NULL, pat_match_auth },
+	{ "method",          NULL,       PAT_MATCH_STR, pat_parse_meth, pat_idx_list_str, NULL, NULL, pat_match_meth },
 
 	{ "path",            "path",     PAT_MATCH_STR },
 	{ "path_beg",        "path",     PAT_MATCH_BEG },