Fixed hang with gifs in duplicates form

metadatamanager.py

@@ -17,11 +17,12 @@ except ImportError:
     exiv2 = None
     HAVE_EXIV2 = False
 
-_app_modified_callback = None
 
 from utils import preserve_mtime
 from constants import RATING_XATTR_NAME, XATTR_NAME
 
+_app_modified_callback = None
+
 MetadataResult = collections.namedtuple('MetadataResult', ['tags', 'rating'])
 EMPTY_METADATA = MetadataResult([], 0)
 
@@ -30,11 +31,13 @@ def set_app_modified_callback(callback):
     global _app_modified_callback
     _app_modified_callback = callback
 
+
 def mark_app_modified(path):
     """Triggers the application-modified callback for a path."""
     if _app_modified_callback:
         _app_modified_callback(path)
 
+
 def notify_baloo(path):
     """
     Notifies the Baloo file indexer about a file change using DBus.