[leo_gateway][leo_storage] Exit when the number of retries reached a certain time

[mocchira]

If a user missed editing configuration for leo_manager's name,
Since this node never succeed in connecting to leo_managers,
Automatically quitting this node with appropriate error messages would be more user friendly.

This issue aim to reduce this kind of mistakes.
https://groups.google.com/forum/#!topic/leoproject_leofs/GkO_D3f-SIo