Ticket #574 - problems with dbcachesize disk space calculation
    
    https://fedorahosted.org/389/ticket/574
    Reviewed by: mreynolds (Thanks!)
    Branch: master
    Fix Description: 50% overhead for dbcachesize is too much - use 10%.
    Based on empirical observations on RHEL 6.4 64-bit bdb 4.7.
    There seems to be no way to ask bdb "Given a dbcachesize, what will be the
    total size of all of the region files?".
    Platforms tested: RHEL6 x86_64
    Flag Day: no
    Doc impact: no