A user reported `kvm_nlist(3)` leaks memory. I found there are two leaks. First, it had to `free(3)` `dpcpu_off` (introduced in rS204494) from `kvm_close(3)`. Second, it is not `free()`'ing temporary buffer introduced in D3341 (rS291406). Also, an unchecked `calloc(3)` failure was fixed while I am in the neighborhood.