Apply defaults to all of the configs. Much fewer .get()s

pre_commit/clientlib/validate_base.py

@@ -4,6 +4,8 @@ import jsonschema.exceptions
 import os.path
 import yaml
 
+from pre_commit.jsonschema_extensions import apply_defaults
+
 
 def get_validator(
     json_schema,
@@ -39,6 +41,8 @@ def get_validator(
                 'File {0} is not a valid file'.format(filename), e,
             )
 
+        obj = apply_defaults(obj, json_schema)
+
         additional_validation_strategy(obj)
 
         return obj