Let get_config() handle env override

Co-authored-by: Marius van den Beek <m.vandenbeek@gmail.com>
(cherry picked from commit 574fa4cb1f)

scripts/check_model.py

@@ -40,7 +40,7 @@ def find_missing_indexes():
     mapping_indexes = load_indexes(metadata)
 
     # create EMPTY metadata, then load from database
-    db_url = os.environ.get("GALAXY_CONFIG_OVERRIDE_DATABASE_CONNECTION") or get_config(sys.argv)['db_url']
+    db_url = get_config(sys.argv)['db_url']
     metadata = MetaData(bind=create_engine(db_url))
     metadata.reflect()
     indexes_in_db = load_indexes(metadata)