Ticket #48025 - add an option '-u' to dbgen.pl for adding group entries with uniquemembers
    
    Usage: /usr/bin/dbgen.pl [options] -o output_file  -n number
    	   -u add groups containing uniquemembers;
    	 	  generate a group for every 100 user entries created that contains the 100 members.
    
    https://fedorahosted.org/389/ticket/48025
    
    Reviewed by mreynolds@redhat.com (Thank you, Mark!!)