schema: Add a special dir away from the data to do schema things

Avoid a potential clash of schema data vs grant data if file names were
the same. Also remove redundant comment about 1.4 release. This has
happened now.

lib360dataquality/cove/schema.py

@@ -29,8 +29,8 @@ class Schema360(SchemaJsonMixin):
     _pkg_schema_obj = {}
     _schema_obj = {}
 
-    def __init__(self, working_dir) -> None:
-        self.working_dir = working_dir
+    def __init__(self, data_dir) -> None:
+        self.working_dir = os.path.join(data_dir, "schema")
 
         self.schema_host = self.working_dir  # required by lib-cove
 
@@ -131,8 +131,6 @@ def resolve_extension(self, json_data) -> Optional[list]:
         Returns an array of extension_infos or None
         """
 
-        # FIXME NOTE this currently requires env SCHEMA_BRANCH=1.4-staging
-
         try:
             extension_ids = json_data["extensions"]
         except KeyError: