fix 'clone' bug when updating jnlp snapshot
fix 'clone' bug when updating jnlp snapshot

In rails >= 3.1, the clone method copies the id, so the code changed here
doesn't actually create a new object, it just modifies an existing one.
This could be replaced with dupe, but that isn't really useful because
all the properties are being modified anyhow.
concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse,concord-consortium/rigse