[REEF-1754] Use finer log level when running unit tests in reef-tests
[REEF-1754] Use finer log level when running unit tests in reef-tests

JIRA: [REEF-1754](https://issues.apache.org/jira/browse/REEF-1754)

closes #1273

dongjoon-hyun/reef,apache/incubator-reef,dongjoon-hyun/incubator-reef,dougmsft/reef,dongjoon-hyun/reef,jwang98052/reef,shravanmn/reef,shravanmn/reef,singlis/reef,dongjoon-hyun/reef,motus/reef,dougmsft/reef,shravanmn/reef,dougmsft/reef,dougmsft/reef,jwang98052/reef,dongjoon-hyun/incubator-reef,anupam128/reef,markusweimer/reef,singlis/reef,apache/incubator-reef,apache/reef,markusweimer/reef,markusweimer/incubator-reef,motus/reef,dongjoon-hyun/incubator-reef,markusweimer/incubator-reef,jwang98052/reef,anupam128/reef,jwang98052/reef,apache/reef,jwang98052/incubator-reef,jwang98052/incubator-reef,dongjoon-hyun/incubator-reef,apache/incubator-reef,dongjoon-hyun/reef,apache/incubator-reef,anupam128/reef,dongjoon-hyun/reef,jwang98052/reef,markusweimer/reef,motus/reef,apache/reef,jwang98052/incubator-reef,markusweimer/reef,anupam128/reef,shravanmn/reef,dongjoon-hyun/reef,jwang98052/incubator-reef,markusweimer/incubator-reef,singlis/reef,singlis/reef,jwang98052/incubator-reef,jwang98052/incubator-reef,apache/reef,shravanmn/reef,anupam128/reef,singlis/reef,dongjoon-hyun/incubator-reef,anupam128/reef,dongjoon-hyun/reef,apache/incubator-reef,apache/reef,singlis/reef,singlis/reef,jwang98052/incubator-reef,dongjoon-hyun/incubator-reef,motus/reef,markusweimer/incubator-reef,motus/reef,jwang98052/reef,apache/incubator-reef,motus/reef,dougmsft/reef,shravanmn/reef,markusweimer/incubator-reef,anupam128/reef,markusweimer/incubator-reef,dougmsft/reef,markusweimer/reef,apache/incubator-reef,apache/reef,shravanmn/reef,markusweimer/incubator-reef,markusweimer/reef,markusweimer/reef,jwang98052/reef,dougmsft/reef,motus/reef,dongjoon-hyun/incubator-reef,apache/reef