fix for issue #501

[mjscosta]

fix for issue #501.

[mjscosta]

Supersedes #506 , I've detected a bug with a call invocation.

Addresses also issues in:
#492
#418

[peterjc123]

Hi, I tried your patch. And looks like the changes have a conflict with the code here. When I log in and the token already exists, the 400 HTTP status code is returned and an exception was thrown by the exception hook. That is not the expected behavior.

[mjscosta]

Thanks, I need check that. I've just used the -t in the command line, did not tried the login command.