Lock is not released when a stale lock is said to release because the wrong uid is used

Problem/Motivation

The following code in \Drupal\content_lock\ContentLock\ContentLock::locking

        // There is a stale lock. Release it.
        if (is_object($lock) && $lock->uid != $uid) {
          $this->release($entity, $form_op, $uid);
        }
        // Save locking into database.
        $this->lockingSave($entity, $form_op, $uid);

does not work because passing $uid is not right - it should be $lock->uid

Steps to reproduce

Take over a stale lock and see that the lock is not released correctly. The later merge in \Drupal\content_lock\ContentLock\ContentLock::lockingSave() overwrites the lock.

Proposed resolution

Pass the correct UID in and test it.

Remaining tasks

User interface changes

API changes

Data model changes