fix _identify_model_variants (huggingface#9247)

merge now, will add/fix test next

Author: yiyixuxu

src/diffusers/pipelines/pipeline_loading_utils.py

@@ -752,12 +752,12 @@ def _fetch_class_library_tuple(module):
 def _identify_model_variants(folder: str, variant: str, config: dict) -> dict:
     model_variants = {}
     if variant is not None:
-        for folder in os.listdir(folder):
-            folder_path = os.path.join(folder, folder)
-            is_folder = os.path.isdir(folder_path) and folder in config
+        for sub_folder in os.listdir(folder):
+            folder_path = os.path.join(folder, sub_folder)
+            is_folder = os.path.isdir(folder_path) and sub_folder in config
             variant_exists = is_folder and any(p.split(".")[1].startswith(variant) for p in os.listdir(folder_path))
             if variant_exists:
-                model_variants[folder] = variant
+                model_variants[sub_folder] = variant
     return model_variants