client: Fail in parse_parcelcfg() if READONLY is set
client: Fail in parse_parcelcfg() if READONLY is set

- Format 4 parcels have a READONLY parcel.cfg option which we're not
going to support in this release.  Bail out in parse_parcelcfg() if
READONLY is not set to 0.

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