v2v: Prevent conversion of "blocked" and "paused" domains also.

Previously only "running" domains were blocked from conversion.
However "blocked" is essentially the same as running (on Xen it just
means the domain is running but waiting on an I/O resource).  And
"paused" domains probably shouldn't be converted either since their
disks are only crash-consistent.
run: Add p2v to the PATH.