fix debug log (#772)

ppdet/data/reader.py

@@ -45,7 +45,7 @@ class Compose(object):
                 data = f(data, ctx)
             except Exception as e:
                 stack_info = traceback.format_exc()
-                logger.info("fail to map op [{}] with error: {} and stack:\n{}".
+                logger.warn("fail to map op [{}] with error: {} and stack:\n{}".
                             format(f, e, str(stack_info)))
                 raise e
         return data

ppdet/utils/check.py

@@ -89,7 +89,7 @@ def check_config(cfg):
 
     actual_num_classes = int(cfg.num_classes) - int(
         train_dataset.with_background)
-    logger.info("The 'num_classes'(number of classes) you set is {}, " \
+    logger.debug("The 'num_classes'(number of classes) you set is {}, " \
                 "and 'with_background' in 'dataset' sets {}.\n" \
                 "So please note the actual number of categories is {}."
                 .format(cfg.num_classes, train_dataset.with_background,