Ticket 367 - Invalid chaining config triggers a disk full error and shutdown
    
    Bug Description:  If you use the root DN for the chaining bind DN a error -2 (LDAP_LOCAL_ERROR)
                      is returned from the callback.  This is the same error code for SLAPI_FAIL_DISKFULL.
                      Once the error -2 is retuned, the server thinks we are out of disk space and the
                      instance is shutdown.
    
    Fix Description:  Return -1, instead of -2(LDAP_LOCAL_ERROR)
    
    https://fedorahosted.org/389/ticket/367
    
    Note:  also did a little code cleanup with indentation
    
    Reviewed by:
    (cherry picked from commit dc379838f8e4cfd2c736e8c2fb8366fb3b4f73d4)