Remove use of storage wrappers

Use a dynamic subclass instead that always deconstructs to a fake
subclass with a __eq__ method that always returns True. This should
trick makemigrations into never creating a new migrations for
changes to the storage class or the arguments.

Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>

mayan/apps/common/classes.py

@@ -72,6 +72,16 @@ class ErrorLogNamespace(object):
         return ErrorLogEntry.objects.filter(namespace=self.name)
 
 
+class FakeStorageSubclass(object):
+    """
+    Placeholder class to allow serializing the real storage subclass to
+    support migrations.
+    """
+
+    def __eq__(self, other):
+        return True
+
+
 class MissingItem(object):
     _registry = []