add cassandra backup script for DC0
add cassandra backup script for DC0

DrXyzzy/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,DrXyzzy/smc,tscholl2/smc,sagemathinc/smc,sagemathinc/smc,tscholl2/smc,sagemathinc/smc,tscholl2/smc,DrXyzzy/smc