Paragraphs don't work because entity has no access callback defined

Problem / motivation

After upgrade Paragraphs to 7.x-1.0-rc4 or 7.x-1.0-rc4+1-dev, paragraphs used in Privatemsg module stops working and message "You are not allowed to add any of the bundles" appeared instead of list of Paragraph Bundles.

The problem persists even after the update Privatemsg module to the latest versions (1.x or 2.x).

Problem analysis

Function paragraphs_paragraphs_item_access() asks for entity_access(). If parent entity (privatemsg) has no 'access callback' defined, entity_access() returns NULL, because "If the entity type does not specify any access information, NULL is returned".

In that case, paragraphs_paragraphs_item_access() returns PARAGRAPHS_ITEM_ACCESS_DENY and function paragraphs_item_access() returns FALSE.

Proposed solutions

Variant A) Use patch for Paragraphs
Variant B) Define access callback in function privatemsg_entity_info() and return an appropriate privileges.