text: Title: replace load_blueprints to a better version
  Body: ``` python
  # coding: utf-8
  import os
  import random
  import logging
  
  from werkzeug.utils import import_string
  
  logger = logging.getLogger()
  
  
  def load_blueprints_from_folder(app, folder_path=None, object_name=None):
      folder_path = (
          folder_path or
          os.path.join(app.root_path, 'blueprints')
      )
      object_name = object_name or app.config.get(
          'BLUEPRINTS_OBJECT_NAME', 'blueprint'
      )
      dir_list = os.listdir(folder_path)
      base_module_name = app.name.replace(".app", "")
      loaded_blueprints = {}
      for fname in dir_list:
          is_valid_module = all([
              not os.path.exists(os.path.join(folder_path, fname, 'DISABLED')),
              os.path.isdir(os.path.join(folder_path, fname)),
              os.path.exists(os.path.join(folder_path, fname, '__init__.py'))
          ])
          if is_valid_module:
              import_name = ".".join([base_module_name, fname, object_name])
              try:
                  blueprint = import_string(import_name)
              except ImportError:
                  app.logger.error("Cannot load %s blueprint", fname)
              else:
                  loaded_blueprints[fname] = blueprint
                  if blueprint.name not in app.blueprints:
                      app.register_blueprint(blueprint)
                  else:
                      blueprint.name += str(random.getrandbits(8))
                      app.register_blueprint(blueprint)
      logger.info("{0} modules loaded".format(loaded_blueprints.keys()))
  ```
  