uniformize log level for all loggers

ml-agents/mlagents/logging_util.py

 import logging
 
 
-def create_logger(name, log_level=logging.INFO):
+def create_logger(name, log_level):
     date_format = "%Y-%m-%d %H:%M:%S"
     log_format = "%(asctime)s %(levelname)s [%(filename)s:%(lineno)d] %(message)s"
 

ml-agents/mlagents/trainers/learn.py

     except Exception:
         print("\n\n\tUnity Technologies\n")
     print(get_version_string())
-    trainer_logger = create_logger("mlagents.trainers", log_level=logging.INFO)
-    env_logger = create_logger("mlagents_envs", log_level=logging.INFO)
-        trainer_logger.setLevel("DEBUG")
-        env_logger.setLevel("DEBUG")
+        log_level = logging.DEBUG
+        log_level = logging.INFO
+
+    trainer_logger = create_logger("mlagents.trainers", log_level)
 
     trainer_logger.debug("Configuration for this run:")
     trainer_logger.debug(json.dumps(options._asdict(), indent=4))