Count ocunit failures as errors in overall test results

We are printing ocunit failures in Failures section but are not counting them as errors in overall test results which could lead to such kind of messages:

  ** RUN-TESTS FAILED: 466 passed, 0 failed, 0 errored, 466 total **

To improve the message we are now counting ocunit failures as errors:

  ** RUN-TESTS FAILED: 466 passed, 0 failed, 30 errored, 496 total **
Merge pull request #350 from facebook/nekto/improve_errors_counter

Count ocunit failures as errors in overall test results