fix: FileSqlManager缺了个无参构造方法

Author: wendal

src/org/nutz/dao/impl/FileSqlManager.java

@@ -38,6 +38,9 @@ public class FileSqlManager implements SqlManager {
 
     protected String pairBegin = "/*";
     protected String pairEnd = "*/";
+    
+    public FileSqlManager() {
+    }
 
     public FileSqlManager(String... paths) {
         this.paths = paths;