Ticket 49105 - Sig FPE when ns-slapd has 0 backends.
    
    Bug Description:  The autotuning system assumed we had 1 or more backends.
    As a result, when you start a server with no backends, a divide by 0 was
    encountered
    
    Fix Description:  Check the backend count before we attempt the division.
    
    https://fedorahosted.org/389/ticket/49105
    
    Author: wibrown
    
    Review by: nhosoi (Thanks!)