Need for a hook_image_path_flush

Problem/Motivation

Modules like adaptive_image have no way of reacting to image_path_flush();

Proposed resolution

I propose adding an extra hook at the end of image_path_flush(), like this:

 module_invoke_all('image_path_flush', $path);

Remaining tasks

• Review and approve

User interface changes

• None

API changes

• New hook_image_path_flush($path) is added.

Data model changes

• None