All paths to EXP_Remove() raise the OC_F_DYING flag to dismiss the
objcore in HSH_Lookup(). A regular purge used to EXP_Rearm() an oc
for immediate (yet delayed) expiry, leaving it to the expiry thread
to apply this flag and call EXP_Remove().

When the regular purge went from EXP_Rearm() to EXP_Remove() in order
to avoid counting purged objects as expired, the OC_F_DYING flag was
overlooked.

Refs 709f71ab