Bulk path generation types overwriting each other for custom entities

Use case

1. Install Entity Construction Kit and Pathauto Entities modules
2. Create few (at least 2) custom entity types
3. Enable those entity types for use with Pathauto (/admin/config/search/path/entities)
4. On Bulk Update page only one custom entity type is displayed, instead of all created in pt 2.

Issue

#options in $form['update'] form element in pathauto_bulk_update_form() are keyed by batch_update_callback value, which is the same for all entity types created using ECK - which means that regardless how many entity types are created (and enabled to be used with Pathauto), only the last one is displayed in the form.

Proposed solution

Key mentioned #options by keys received from module_invoke_all('pathauto', 'settings') call.

Patch to follow.