In order to keep things simple and clear, enforce the
following test results rules:

 * `PASS`: the test passed, which means all conditions
   being tested have passed.
 * `FAIL`: the test failed, which means at least one
   condition being tested has failed. Ideally, it should
   mean a problem in the software being tested has been found.
 * `ERROR`: an error happened during the test execution.
   This can happen, for example, if there's a bug in the test
   runner, in its libraries or if a resource breaks unexpectedly.
   Uncaught exceptions in the test code will also result in this
   status.
 * `SKIP`: the test runner decided a requested test should not
   be executed. This can happen, for example, due to missing
   requirements in the test environment or when there's a job
   timeout.

In order to do that, let's not make the behavior on exceptions
other than TestFail to be configurable. Therefore, the config
value uncaught_exception_result must be removed and the status
of the test always be 'ERROR'.
Signed-off-by: NLucas Meneghel Rodrigues <lmr@redhat.com>

On unhandeled unknown exceptions the test should finish with ERROR
rather than FAIL as the test developer didn't think it might happen.

This behavior is configurable in config when the user have a different
opinion.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>