changing delete to use bulk operation and minor refactoring
changing delete to use bulk operation and minor refactoring

dimagi/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq,qedsoftware/commcare-hq