gb_storage: more cleanup and ability to delete snapshots
gb_storage: more cleanup and ability to delete snapshots

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