fixed a bug that caused emtpy referral date to give an unhelpful error message
fixed a bug that caused emtpy referral date to give an unhelpful error message

qedsoftware/commcare-hq,qedsoftware/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,dimagi/commcare-hq,puttarajubr/commcare-hq,gmimano/commcaretest,SEL-Columbia/commcare-hq,qedsoftware/commcare-hq,gmimano/commcaretest,SEL-Columbia/commcare-hq,qedsoftware/commcare-hq,gmimano/commcaretest,puttarajubr/commcare-hq,dimagi/commcare-hq,SEL-Columbia/commcare-hq,dimagi/commcare-hq,qedsoftware/commcare-hq