Avoid throwing OrmException from SubmitRuleEvaluator methods

Instead of lazily looking up the patch set (possibly throwing)
wherever it is used, initialize it once at the beginning of each
public method (other than the trivial setters). and convert any
OrmExceptions to error records of the appropriate type.

Change-Id: I303c4d90d7b1aeaeb5cf33b1a4031a6bef8fa1a3