Handle errors/exceptions from Server gracefully

[sagarsane]

Whenever we run a Grabbit job and if server fails to send the path requested (various reasons; like The requested path was not found, Could not access the requested path, Some other error during sending the requested path.), we do not transmit that information from Server to Client in order to inform the client that something failed.

This can be handled more gracefully. For example; if a path is not found; we can send a 404 from Server back to the Client with a proper message about what happened. This way; we can also further enhance the Client Grabbit Job Status API to include such messages in case of job failures.