making status_hash test more precise: assert_nil for invalid uuids
making status_hash test more precise: assert_nil for invalid uuids

compwron/resque-status,compwron/resque-status,georgemillo/resque-status,nathan-v/resque-state,nathan-v/resque-state,quirkey/resque-status,quirkey/resque-status,georgemillo/resque-status