[Yanel-usage] Allow other users (than oneself) to delete checkout locks

[Michael Wechner]

Hi

I have implemented the functionality to allow other users  than oneself 
to delete checkout locks,
whereas one has to set the following permission within an access policy 
(e.g. ROOT policy)

 <usecase id="release-lock">
   <user id="alice" permission="true"/>
 </usecase>

Cheers

Michi