Ticket #605 - support TLS 1.1 - lower the log level for the supported NSS version range
    
    Description: Supported NSS version range was logged with SLAPI_LOG_
    FATAL at the startup, which may not be always needed.  Thus, this
    patch is lowering the log level to SLAPI_LOG_CONFIG.
    
    https://fedorahosted.org/389/ticket/605
    
    Reviewed by mareynol (Thank you, Mark!!)