are two ways this can happen.

1. When allocating the proxy nodes before getting the tickets. This is
   just like the local node case; need to go around the loop again and
   retry with a new node set. 

2. When getting the tickets, someone else got the nodes and gthe
   getticket fails. This is a lot like case 1, but now we have to
   nfree the proxy node, and tell the mapper to try again.