TRQ-2622. Fix two potential scenarios for jobs getting stuck in an exiting state.
TRQ-2621. Job dependencies weren't being resolved after a qdel.

During test fest I found that if I qdel'ed the first job in a dependency list the jobs all stayed
held indefinitely. This didn't seem like useful behavior so I added a called to depend_on_term()
when we delete jobs in response to a qdel.