isr_admin: Add helper function to find the current parcelverdir
isr_admin: Add helper function to find the current parcelverdir

- Move code to find the current version directory of a parcel from
copyparcel() into a helper function

cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr,cmusatyalab/openisr