conf/completion: Don't autocomplete parcel unless appropriate
conf/completion: Don't autocomplete parcel unless appropriate

- Don't autocomplete a parcel name or UUID if one has already been specified
on the command line, or if we are in the next word after an option which
takes a parameter

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