A set of changes to make swapmod work on jailed nodes (note, swapmod
does not yet work with remove virtual nodes; that will take even more work). Added a new allocstate called RES_TEARDOWN. assign_wrapper no longer deallocates unused nodes, but rather moves them into the new state for the wrapper (tbswap) to deal with. Thats cause deleted vnodes need to be torn down, since its possible that the node on which they were living will not be deallocated (say, if there are other vnodes on it). We do not want to be doing that from assign_wrapper, so tbswap looks for those nodes. Made vnode_setup allocstate aware in the same way that os_setup is; do not reboot vnodes or try to set up vnodes when they are already in the RES_READY state, as they will be when doing a swapmod. In addition, if os_setup is going to reboot the underlying physnode, move the vnodes on that node into RES_READY too, since there they will setup automatically. Might need an interim state here, for correctness.