owncloud/core

Bugfix: Handle exception when adding mount to existing cache or lock

In some cases there are can be multiple parallel requests that could in
their logic attempt to create shared file mountpoint for the file or 
to create lock, e.g. collaboration software. Exception to add cache or 
lock that already exists is now handled

https://github.com/owncloud/core/pull/40192
https://github.com/owncloud/enterprise/issues/5198