Trac Ticket #409 - Report during startup if nsslapd-cachememsize is too small
    
    https://fedorahosted.org/389/ticket/409
    
    Fix description: adding a code to compare the entry cache size with
    the main db file (id2entry.db) size.  If the entry cache size is
    less than the db file size, it logs the warning in the error log.
    (cherry picked from commit 950c0c6bf7515e02f88543e8f477ec717725849f)