548535 - memory leak in attrcrypt
    
    https://bugzilla.redhat.com/show_bug.cgi?id=548535
    
    Description:
    The attrcrypt module maintains the inst_attrcrypt_state_private
    field in the instance structure (ldbm_instance) to store the private
    keys.  The area and the space for the private keys are allocated in
    attrcrypt_init which is called from dblayer_instance_start.
    A backend instance could be closed and restarted multiple times
    (for instance, in the bulk_import, which is used by the replica
    initialization), but the area had no chance to be freed.
    This patch is adding the clean-up code.