Fixed hhash index free with custom mm_ctx and lookup.

src/common/hhash.c

@@ -375,7 +375,7 @@ void hhash_build_index(hhash_t* tbl)
 	/* Free old index. */
 	if (tbl->index) {
 		if (tbl->mm.free) {
-			free(tbl->index);
+			tbl->mm.free(tbl->index);
 		}
 		tbl->index = NULL;
 	}

src/libknot/zone/zonedb.c

@@ -157,6 +157,7 @@ knot_zone_t *knot_zonedb_find_suffix(knot_zonedb_t *db, const knot_dname_t *dnam
 			break;
 		}
 		dname = knot_wire_next_label(dname, NULL);
+		--zone_labels;
 	}
 
 	return ret;