Ticket 47369  version2 - provide default syntax plugin
    
    Bug Description:  syntax plugins are laoded during bootstrapping, but
    			in that phase already attributes are handled
    			eg in dse.ldif and schema files and no proper way
    			to normalize or comare values is provided.
    			This became visible with teh fix for ticket #346
    			where large attribute sets will be sorted
    
    Fix Description:   when the first attribute syntax init is done, create a plugin
    			for directory string syntax and register it with a dummy
    			attribute name. if for any attribute the syntax lookup fails
    			fall back to using this plugin.
    			It will only be used until the syntax plugins are loaded
    			and in the startup phase it is acceptable to use directory
    			string.
    			The impelemenation of the default plugin is reduce to the
    			necessary minimum not to duplicate the code of the syntax
    			plugins.
    
    			A more rigorus solution would be to refactor the code and
    			and move the common code from the syntax plugin to the
    			slapd level and reuse it in the default plugin.
    			But this would be a major change and should only be done
    			with a review of the syntax plugin code, whic could probabyly
    			be optimized.
    
    https://fedorahosted.org/389/ticket/47369
    
    Reviewed by: RichM