Adding Cases in Drupal requires permission 'access all cases and activities'. Add an explicit 'add cases' permission

A user should be able to add a case without having access to all cases

I've added a new permission for CiviCase: 'add cases'. Either this permission OR 'access all cases' is required to add a case. Change affects Case menu (New Case), as well as Create New block items and Actions button on Contact Summary.

From line148 of CRM/Case/Form/Case.php
if ( ($this->_action & CRM_Core_Action::ADD) &&
!CRM_Core_Permission::check( 'access all cases and activities' ) )

{ CRM_Core_Error::fatal( ts( 'You are not authorized to access this page.' ) ); }

'access all cases and activities' should be 'access my cases and activities'