Disable triggers for invalid auth when using custom auth handler

[dubee]

When using a custom auth handler, the provider will encounter an exception when invalid credentials are supplied. The provider then gets stuck in an infinite exception loop since the consumer will restart after every exception.

Example log lines displaying this problem:

...Firing trigger with 6 messages 
...Uncaught exception: 'access_token' 
...Consumer stopped without being asked 

[jasonpet]

LGTM