Filesystem Storage Class ignores settings changes

[Tony Flury]

In situations where the settings (such as MEDIA_ROOT) changes the FilesystemStorage class should ideally reflect those changes.

It is clear from the Source code that this class ignores all settings changes.

This hampers testing - effectively making the @override_setting decorator pointless when used to override MEDIA_ROOT - although this is not mentioned in the documentation.

[Tim Graham]

Looks like a duplicate of #26038 which is fixed in Django 1.10.