Manages BeanLocks. All BeanLocks have a reference count.
When the reference count goes to 0, the lock is released from the
id -> lock mapping.
author: Bill Burke author: Marc Fleury author: Scott.Stark@jboss.org
returns the lock associated with the key passed. If there is
no lock one is created this call also increments the number of
references interested in Lock.
WARNING: All access to this method MUST have an equivalent
removeLockRef cleanup call, or this will create a leak in the map,