Add log statements for policy check failures

Misconfiguration of the policy.json file may
cause policy check failures. It's kind to the
developer to log the underlying exception
so that he/she can have more information as to
how to address the problem.

Closes bug: #1246139

Change-Id: I8664959cb98b3a41d159db3acb91da9baba810ae
Merge "Add log statements for policy check failures"