New DEBUG facility - new levels
    
    https://fedorahosted.org/sssd/ticket/925
    
    Added functions:
    - debug_convert_old_level() to convert levels 0-9 to appropriate bitmask
      debug_convert_old_level(5) returns 0x03F0 (= 0 | 1 | 2 | 3 | 4 | 5)
    
    - debug_get_level() to convert old level number to its new value
      debug_get_level(5) returns 0x0200 (= 5)
    
    There are several new macros in util/util.h:
    
    - SSSDBG_* to reflect a debug level (same names as in the ticket) - please,
      don't use magic numbers anymore