Continue the objectification of the swapdev backends:
Continue the objectification of the swapdev backends:

Remove the vnode and dev_t fields and replace them with a void *.

Introduce separate strategy functions for devices and regular (NFS)
vnodes.

For devices we don't need the vnode v_numoutput stuff.

Add a generic swaponsomething() function to add a swapdevice and
split the remainder of swaponvp() into swaponvp() and swapondev()
which calls this backend.

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase