Revert "Return 412 instead of 404 on bad sync."
Revert "Return 412 instead of 404 on bad sync."

This reverts commit e06d1d5f2df6a593380f791336af6acc0094e693.

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