Index: django/db/models/fields/files.py
===================================================================
--- django/db/models/fields/files.py	(revision 9846)
+++ django/db/models/fields/files.py	(working copy)
@@ -20,7 +20,7 @@
         self.instance = instance
         self.field = field
         self.storage = field.storage
-        self._name = name or u''
+        self._name = name
         self._closed = False
         self._committed = True
 
@@ -175,7 +175,7 @@
     def get_db_prep_value(self, value):
         "Returns field's value prepared for saving into a database."
         # Need to convert File objects provided via a form to unicode for database insertion
-        if value is None:
+        if value == None:
             return None
         return unicode(value)