Stabilized communicator.fetch_managers()
Closes #206 (closed)
Seems like the IceGridAdminPrx dies after some time which causes an irrecoverable CouldNotFetchException when fetching managers.
With this MR the communicator tries to recover by getting a new IceGridAdminPrx. Only if this fails the CouldNotFetchException is thrown. Seems to fix the instability problem. Added appropriate logging.