[SPARK-2403] Catch all errors during serialization in DAGScheduler

https://issues.apache.org/jira/browse/SPARK-2403

Spark hangs for us whenever we forget to register a class with Kryo. This should be a simple fix for that. But let me know if you have a better suggestion.

I did not write a new test for this. It would be pretty complicated and I'm not sure it's worthwhile for such a simple change. Let me know if you disagree.

Author: Daniel Darabos <darabos.daniel@gmail.com>

Closes #1329 from darabos/spark-2403 and squashes the following commits:

3aceaad [Daniel Darabos] Print full stack trace for miscellaneous exceptions during serialization.
52c22ba [Daniel Darabos] Only catch NonFatal exceptions.
361e962 [Daniel Darabos] Catch all errors during serialization in DAGScheduler.