Ticket 408 - Fix crash when disabling/enabling the setting
    
    Bug Description:  Enabling/disabling can lead to crash as the setting
                      was not designed to be dynamically updated.
    
    Fix Description:  Do not use the actual config setting to determine if the
                      cache is enabled.  Instead we record when the cache is
                      initialized.  The server still needs to be restarted for
                      the config change to take effect.
    
                      Also freed the cache at server shtudown.
    
    https://fedorahosted.org/389/ticket/408
    
    Reviewed by: rmeggins(Thanks!)
    (cherry picked from commit 03c90f04065059ee310e9fa7d98228e0aa39fa50)
    (cherry picked from commit 50ad64a442495810a84558c6c17dcc2263b815b6)
    (cherry picked from commit e0d85bead832c6aa7a2ec01157ab786a53fb5272)